231 F.3d 1049 (7th Cir. 2000)
FANNIE B. KALIS, Plaintiff-Appellant,v.COLGATE-PALMOLIVE COMPANY, MILLEN TRUE VALUE HARDWARE  and MILLEN HARDWARE, Defendants-Appellees.
No. 99-3343
In the  United States Court of Appeals  For the Seventh Circuit
Argued April 14, 2000Decided November 3, 2000

Appeal from the United States District Court  for the Northern District of Illinois, Eastern  Division.  No. 95 C 7673--Sidney I. Schenkier, Magistrate  Judge.[Copyrighted Material Omitted]
Before POSNER, RIPPLE and ROVNER, Circuit  Judges.
RIPPLE, Circuit Judge.


1
Fannie B. Kalis  brought this products liability action  against Colgate-Palmolive Company  ("Colgate") and other defendants1 for  injuries caused by the explosion of a  container of fondue fuel. Colgate moved  for summary judgment on the ground that  Ms. Kalis could not establish that  Colgate manufactured the product that  caused her injury. The district court  granted Colgate's motion, and Ms. Kalis  appealed. For the reasons set forth in  the following opinion, we affirm the  judgment of the district court.


2
* BACKGROUND

A.Facts
1.

3
In April 1986, Ms. Kalis' mother, Nancy  Kalis ("Mrs. Kalis"), purchased liquid  fondue fuel from a local hardware store  to use at an upcoming party for Ms.  Kalis' older sister, Jennifer. During the  party, the flame under the fondue pot  went out, and Mrs. Kalis attempted to  relight it. When she did so, the  container of liquid fondue fuel exploded  and caused severe injuries to Ms. Kalis.  Within a few days of the accident, either  Jennifer or Mrs. Kalis discarded the  fondue pot and fuel container.


4
Nearly ten years later, on December 28,  1995, Ms. Kalis brought this action  against Colgate. In her complaint, Ms.  Kalis alleged that Colgate, as  manufacturer of the fondue fuel and  container, was responsible for her  injuries on theories of negligence,  breach of warranty, and strict liability.  On October 23, 1996, the district court  issued a preliminary pretrial scheduling  order that set forth some procedural  agreements of the parties, including the  decision that "this case may be tried by  the assigned Magistrate Judge." R.22 at  4. Ms. Kalis later executed a more formal  consent to adjudication by a magistrate.  See R.24. Specifically, Ms. Kalis'  counsel agreed that: "In accordance with  the provisions of 28 U.S.C. sec. 636(c)  and Fed. R. Civ. P. 73, the above named  . . . parties . . . hereby voluntarily  consent to have a United States  magistrate judge conduct any and all  further proceedings in the case,  including the trial, and entry of a final  judgment." Id.


5
More than a year later, the district  court conducted a status hearing.  According to the accompanying minute  entry, the hearing was "held and  continued to 9:30 a.m. on 1/13/98. Non  expert discovery to be completed by  2/13/98. . . ." Minute Entry of December  5, 1997. During the course of discovery,  Colgate propounded interrogatories to Ms.  Kalis that, among other information,  requested a description of any details  concerning the fondue fuel container used  at the party. In response, Ms. Kalis did  not state that the fuel was manufactured  by Colgate; rather, she stated that it  was a generic type of liquid fondue fuel,  in a white-yellow, pint-sized container,  which bore the trade or brand name "True  Value."


6
Colgate also deposed Mrs. Kalis, who  testified that she could not recall  details concerning the fuel container,  other than its height (eight to nine  inches) and color (yellow). Mrs. Kalis  indicated that she thought the container  was cylindrical in shape, but was not  sure. She did not know how the container  was packaged or the amount of fuel it  held. She further testified that she did  not recall seeing any type of brand name  or warnings on the package. As to  thematters on which Mrs. Kalis lacked  recollection, she indicated that she  could not think of anything that would  refresh her memory of the fuel or fuel  container that she had purchased nearly  twelve years earlier.


7
In November 1997, Colgate served on Ms.  Kalis amended requests to admit. These  requests asked that Ms. Kalis admit that  she lacked knowledge "of any written  representations on the packaging of the  product." R.49, Ex.D, Plaintiff's  Response to Colgate's Amended Request to  Admit at 1. Ms. Kalis failed to respond  to the requests within thirty days after  service, and the requests therefore were  deemed admitted. See R.69 at 16.

2.

8
One month after the close of discovery,  on March 13, 1998, Colgate moved for  summary judgment. The crux of Colgate's  motion was that Ms. Kalis had failed to  come forth with any evidence that Colgate  manufactured the fuel or the fuel  container that caused her injuries.  According to an order entered that same  day, the district court set a briefing  schedule that required Ms. Kalis to file  her responsive brief by May 11, 1998.


9
Despite the court's order, no answer was  filed within the allowed time period, and  the docket does not reflect a motion for  extension of time to respond to Colgate's  motion for summary judgment. Instead, on  June 10, 1998, Ms. Kalis moved to stay  briefing on the summary judgment motion  and to seek additional discovery. In her  motion, Ms. Kalis stated that her  mother's memory regarding the brand of  fondue fuel had been refreshed after  examining color photocopies of Sterno-  brand liquid fondue fuel.2 Ms. Kalis  attached an affidavit by her mother in  which Mrs. Kalis stated that her  recollection concerning the manufacturer  of the fuel and fuel container had been  refreshed. She now believed "that the  product which I bought in April 1986 at  Millen True Value Hardware in Wilmette,  Illinois was Sterno liquid fondue fuel in  a container the same as or very similar  to the one depicted in the photocopies my  lawyer showed to me." R.47, Ex.A at 2.  The pictures used to refresh Mrs. Kalis'  memory were attached to the affidavit.


10
In her moving papers, Ms. Kalis stated  that she now believed Millen's Hardware  Store sold only one brand of fondue fuel  at the time she was injured.  Consequently, Ms. Kalis asked the  district court to suspend briefing for  ninety days and to permit the completion  of discovery directed to prove this  theory. Ms. Kalis also sought an order  compelling Colgate to answer outstanding  discovery requests concerning the  identity of the manufacturer and  distributor of the Sterno fuel and  container.3 The court denied the  motion without an opinion, but extended  the response time for the motion for  summary judgment until June 30, 1998.


11
Ms. Kalis filed her response on June 30,  1998. In addition to other materials in  opposition to the motion for summary  judgment, Ms. Kalis attached her mother's  affidavit, amended answers to Colgate's  interrogatories, and belated answers to  Colgate's amended requests to admit.  Colgate timely filed its reply brief on  July 14, 1998 and also filed an  accompanying motion to strike both Mrs.  Kalis' affidavit and Ms. Kalis' answers  to the requests for admissions.

B. District Court's Disposition
1.

12
After failed settlement attempts, the  district court ruled on the summary  judgment motion on May 10, 1999. The  court agreed with Colgate that Ms. Kalis  had "failed to identify evidence  sufficient to permit a jury to reasonably  conclude that Colgate manufactured or  supplied the fondue fuel that exploded on  April 15, 1986." R.69 at 9. Ms. Kalis,  the district court explained, "plainly  understands that this is so, and for that  reason has sought to avoid summary  judgment by including in her response two  items--never produced during discovery--  that plaintiff claims creates a genuine  issue of material fact concerning whether  Colgate manufactured the fuel: (a) the  affidavit of Nancy Kalis . . . and (b) a  response to amended request to admit. . .  ." Id. at 10. The court then addressed  whether these two submissions should be  considered.


13
With respect to the affidavit, the  district court believed that it  contradicted earlier testimony4 and  appeared to be filed solely to create a  question of material fact to survive  summary judgment. After reviewing this  court's decisions in Buckner v. Sam's  Club, Inc., 75 F.3d 290 (7th Cir. 1996),  and Adusumilli v. City of Chicago, 164  F.3d 353 (7th Cir. 1998), the district  court determined that Mrs. Kalis had not  offered a "plausible explanation for the  discrepancy" between her earlier  testimony and the affidavit and therefore  disregarded the affidavit. R.69 at 14  (internal quotation marks and citations  omitted).


14
The court also noted that the  photographs used to refresh Mrs. Kalis'  recollection, attached as exhibits to the  affidavit, were not produced prior to the  close of discovery. Because Ms. Kalis  offered no justification for why the  photographs were not used or produced  during the course of over two years of  discovery, the court held that allowing  her to use them would prejudice Colgate  and would violate the court's discovery  orders.


15
The court then turned to Ms. Kalis'  attempt to file belated responses to the  requests to admit. The requests had been  deemed admitted by operation of law  thirty days after they were served.  Contrary to these admissions, Ms. Kalis  claimed that her attorney possessed color  photocopies of a yellow container of  Sterno fondue fuel and that, as a result  of viewing these photographs, she had  knowledge of the writings on the  container. The court found that Ms. Kalis  "ha[d] offered no excuse for [the] tardy  reply (which [was] simply tendered  without seeking leave of court). If  counsel wished to withdraw the  admissions, the 'proper procedural  vehicle' would have been a motion under  Rule 36(b)." Id. at 17. Because Ms. Kalis  was using the affidavit to undo the  effect of the default admissions, and  because Ms. Kalis had not established a  basis for retracting her earlier default  admissions, the court granted the motion  to strike plaintiff's responses to the  requests to admit.


16
The court then summarized its findings  with respect to the evidentiary issues.  "Without the affidavit, plaintiff is left  swimming in a sea of ambiguous  descriptions, conflicting descriptions,  and failed memories about the allegedly  defective fondue fuel and its  manufacturer." Id. at 15. Consequently,  the district court held that Ms. Kalis  had not brought forth sufficient evidence  to warrant a trial.


17
The court next turned to the alternative  basis for judgment, raised by Colgate in  its reply, that under Illinois law "the  absence of the actual product in a  product liability action is a sufficient  ground for granting summary judgment for  the defendants." Id. at 17. The district  court held that the absence of the  container "would affect Colgate's ability  to contest the source of the manufacture  of [the] items; it would affect Colgate's  ability to defend against the charges of  negligence and warranty . . . ; and it  would affect Colgate's ability to raise  other potential defenses." Id. at 22.  Given this prejudice, the district court  concluded that "under governing Illinois  law[,] plaintiff would not be allowed to  proceed with this case in the absence of  the fuel and container. Accordingly, this  provides an independent and alternative  basis for the Court's grant of summary  judgment to Colgate." Id. at 23.

2.

18
After the court's summary judgment order  issued, Ms. Kalis then filed a motion for  reconsideration. In her motion, Ms. Kalis  argued that the district court should  have considered the affidavit and answers  to the requests for admissions. Even in  the absence of these documents, however,  Ms. Kalis believed that summary judgment  was inappropriate because discovery  strongly suggested that Colgate was the  only manufacturer of liquid fondue fuel  in the Chicago area in 1986. The district  court, however, noted that, if existing  discovery responses supported this  theory, Ms. Kalis would not need  additional discovery to prove her theory.  As well, the district court stated that  Ms. Kalis had not explained "why, during  that lengthy [discovery] period, she  failed to obtain the discovery that she  now claims would allow her to demonstrate  a triable issue of fact." R.78 at 4. The  court also rejected Ms. Kalis' argument  that summary judgment should have been  denied because Colgate had failed to  respond to her discovery requests. It  stated: "If plaintiff believed that  Colgate failed to comply with discovery,  then the time to raise that issue would  have been during the pendency of  discovery. . . . Such an argument could  have been made during the pendency of the  summary judgment motion but was not, and  therefore will not be considered further  on this motion to reconsider." R.78 at 4-  5 n.2. The district court concluded that  Ms. Kalis had not brought forward any new  issues that compelled it to reconsider  entry of judgment on behalf of Colgate;  the district court therefore denied Ms.  Kalis' motion to reconsider.

II
DISCUSSION

19
Ms. Kalis claims several errors in the  district court's disposition. First, she  maintains that the district court abused  its discretion in striking Mrs. Kalis'  affidavit. Second, she argues the  district court erred in ruling on the  summary judgment motion in the face of  her request for additional discovery.  Third, she believes that the district  court erred in holding that the absence  of the fuel container would constitute an  absolute bar to recovery under Illinois  law. Finally, she states that the  magistrate judge did not have the  authority to enter summary judgment. We  address each of her contentions in turn.

A. Mrs. Kalis' Affidavit

20
Ms. Kalis first argues that the  affidavit submitted by her mother in  support of the motion for additional  discovery merely supplements and  clarifies prior sworn testimony, and the  district court therefore erroneously  struck the affidavit as contradicting her  mother's prior testimony. We review a  district court's decision to strike or  disregard parts of an affidavit in  opposition to a motion for summary  judgment for an abuse of discretion. See  Adusumilli v. City of Chicago, 164 F.3d  353, 359 (7th Cir. 1988). "Under this  standard, '[d]ecisions that are  reasonable, i.e., not arbitrary, will not  be questioned. . . .'" Id. (citations  omitted).


21
Here the district court carefully  evaluated the answers to the  interrogatories as well as the prior  deposition testimony of Mrs. Kalis to  determine whether there were  contradictions between the discovery  responses and the affidavit. In her  interrogatory answers, Ms. Kalis  identified the brand name of the fondue  fuel that exploded and injured her as  "True Value." During her deposition, Mrs.  Kalis disclaimed any knowledge of the  manufacturer, shape, or volume of the  container for the fuel. She also stated  that she could think of nothing that  would refresh her recollection concerning  the brand name of the fuel. However, in  her affidavit, Mrs. Kalis stated that,  after viewing photocopies of pictures  shown to her by counsel, she "now  believe[s] that the product which [she]  bought in April 1986 at Millen True Value  Hardware in Wilmette, Illinois was Sterno  liquid fondue fuel in a container the  same as or very similar to the one  depicted in the photocopies [her] lawyer  showed to [her]." R.49, Ex.C at 2.


22
"As a general rule, the law of this  circuit does not permit a party to create  an issue of fact by submitting an  affidavit whose conclusions contradict  prior deposition or other sworn  testimony." Buckner v. Sam's Club, Inc.,  75 F.3d 290, 292 (7th Cir. 1996).  Consequently, we must determine whether  Mrs. Kalis' affidavit contradicts her  prior sworn testimony. In doing so, we  find our decision in Buckner v. Sam's  Club, Inc. instructive. In Buckner, a  plaintiff had stepped on an object which  caused her to fall and injure herself;  despite a search, the item that caused  the fall was never recovered. When  deposed, Mrs. Buckner stated that she did  not know what the object was, but  described it as "something uneven and  faulty" and then as a "lump" under her  foot. Id. at 292. In a later affidavit in  opposition to a motion for summary  judgment, however, Mrs. Buckner stated  that she stepped on a small object that  "'felt to be about the size of a ladies  watch, which is one of the types of items  that were on the display tables.'" Id.  The district court in Buckner excluded  the affidavit as a "'clear attempt by  plaintiffs to shore up obvious gaps in  their prima facie case with phantom  evidence' that was contradictory to her  sworn deposition testimony." Id. In  upholding the district court's ruling,  this court noted


23
In the context of opposing a motion for  summary judgment, and when contrasted  with a clear prior statement disclaiming  knowledge of the object, this highly  specific description appears to be an  effort to undo (contradict) the effects  of the deposition testimony and thereby  establish the missing causal link between  the store and the fall. This is certainly  a conclusion the district court could  have rationally made, which for purposes  of our review was not an abuse of  discretion.


24
Id. at 293.


25
The same is true here. Mrs. Kalis has,  from the beginning, disclaimed any  knowledge of the manufacturer of the fon  due fuel and never was able to identify  an object or document that might refresh  her memory. However, long after the close  of discovery, Mrs. Kalis viewed pictures  provided by Ms. Kalis' attorney, those  pictures allegedly refreshed her memory,  and Mrs. Kalis was then able to state  conclusively that "Sterno" was the brand  name on the bottle. Like the affidavit  presented in Buckner, Mrs. Kalis'  affidavit does not function to clarify  prior statements, but it "appears to be  an effort to undo (contradict) the  effects of the deposition testimony."  Id.; see also Adusumilli, 164 F.3d at 360  (upholding district court's action in  striking affidavit as contradicting prior  testimony where the affidavit reported  incidents of sexual harassment and the  plaintiff previously had testified that  she "[could] not recall any incidents of  harassment in 1992"); Slowiak v. Land  O'Lakes, Inc., 987 F.2d 1293, 1296 (7th  Cir. 1993) (finding a "direct  contradiction" between an antitrust  plaintiff's deposition testimony that "he  could not remember any specific instance  in which he wanted to charge more but  didn't" and his affidavit statement that  "'[i]f Schweigert had not fixed the price  that I had to charge my customers, there  would have been many occasions on which I  would have charged more for many of the  Schweigert products I sold'"). Here, the  district court's application of our  "well-established rule" that affidavits  in conflict with prior sworn testimony  should be disregarded was not an abuse of  discretion. Adusumilli, 164 F.3d at 360.

B. Denial of Motion to Extend Discovery

26
Ms. Kalis next argues that the district  court erred in denying her request for  additional discovery before it ruled on  Colgate's summary judgment motion.  Specifically, Ms. Kalis requested that  the district court allow her additional  time for discovery to test her theory  that Millen Hardware Store sold only  Sterno-brand fondue fuel in 1986. She  also requested that the district court  compel Colgate to answer outstanding  discovery requests. "'Our standard  ofreview for the district court's  decision not to allow additional pretrial  discovery is abuse of discretion.'" FDIC  v. American Cas. Co. of Reading, 998 F.2d  404, 407 (7th Cir. 1993) (citing Olive  Can Co. v. Martin, 906 F.2d 1147, 1152  (7th Cir. 1990)).


27
Both the timing and substance of the  motion lead us to conclude that the  district court did not abuse its  discretion in denying it. Discovery  closed on February 13, 1998. One month  later, on March 13, 1998, Colgate filed  for summary judgment. By minute entry of  March 24, 1998, the district court  ordered Ms. Kalis to file her answer  brief by May 11, 1998. On June 10, 1998,  nearly one month after Ms. Kalis should  have filed her answer brief, Ms. Kalis  filed her motion to stay briefing and for  other relief. Thus, the issue of  additional discovery was raised for the  first time almost four months after the  close of discovery and nearly one month  after Ms. Kalis' response to the summary  judgment motion should have been filed.


28
Furthermore, Ms. Kalis did not present  any compelling arguments for allowing her  to conduct additional discovery. In her  motion, Ms. Kalis did not come forward  with any reason why the photographs,  which had refreshed Mrs. Kalis'  recollection and prompted interest in a  new factual theory, had not been found or  presented earlier. Furthermore, Ms. Kalis  did not come forward with any reason why,  in the two and one-half years of  discovery, she was not able to garner  evidence regarding the types of fondue  fuel sold at Millen's Hardware Store--a  theory that did not depend on Mrs. Kalis'  recollection. We cannot fault the  district court for denying Ms. Kalis'  motion when no effort was made to present  the issue to the court in a timely  fashion and when no effort was made to  explain why the requested discovery could  not have taken place within the original  discovery period.


29
Ms. Kalis also intimates that Colgate  thwarted her effort to obtain needed  information by failing to answer  interrogatories and requests for  production that she had propounded.5  According to papers filed in the  districtcourt, Ms. Kalis claims to have  forwarded these discovery requests to  Colgate on November 13, 1997. Although  she did not receive any responses to  these requests, her counsel did not  contact Colgate concerning these alleged  deficiencies until February 2, 1998, a  date that counsel recognized was less  than two weeks before the discovery cut  off.6 Ms. Kalis did not bring the  issue before the district court for  another four months when, on June 10,  1998, she filed her motion to stay  briefing and for other relief. In the  course of her motion, Ms. Kalis' counsel  represented that "[t]o plaintiff's  attorney's knowledge, this court has not  cutoff fact discovery," R.47 at 5, and  requested that the court compel Colgate  to answer the discovery served.


30
The district court took the view that  Ms. Kalis' attempt to secure discovery  from Colgate was belated. See R.78 at 4-5  n.2. Indeed, Ms. Kalis did not raise the  issue until after the close of discovery,  after a motion for summary judgment had  been filed, after a briefing schedule had  been set, and after her time for response  had come and gone. We do not believe that  the district court abused its discretion  in considering the summary judgment  motion, without first compelling  discovery, when Ms. Kalis had been so lax  in asserting her rights. See Brill v.  Lante Corp., 119 F.3d 1266, 1269, 1275  (7th Cir. 1997) (holding that district  court did not abuse its discretion in  entering summary judgment for defendant,  despite the defendant's alleged lack of  response to plaintiff's discovery  requests, where plaintiff filed motion to  compel three months after close of  discovery and three weeks after motion  for summary judgment was filed); cf. JOM,  Inc. v. Adell Plastics, Inc., 193 F.3d  47, 51 (1st Cir. 1999) (holding that  party could not wait until the eve of  trial to contest allegedly deficient  discovery requests). In addition to Ms.  Kalis' lack of diligence, she failed to  comply with the requirements of Federal  Rule of Civil Procedure 37 for bringing a  motion to compel. Specifically, Rule 37  requires that a motion to compel "must  include a certification that the movant  has in good faith conferred or attempted  to confer with the person or party  failing to make the discovery in an  effort to secure the information or  material without court action." Fed. R.  Civ. P. 37(a)(2)(B). Ms. Kalis' June 10  motion did not include a Rule 37(a)  certification, and, consequently, the  district court did not abuse its  discretion in denying that motion.


31
C. Motion to Strike Answers to Requests to  Admit


32
Ms. Kalis also takes issue with the  district court's failure to consider her  belated answers to Colgate's requests for  admissions. As with other discovery  matters, we review the district court's  decision on this issue for an abuse of  discretion. See American Auto. Ass'n  (Inc.) v. AAA Legal Clinic of Jefferson  Crooke, P.C., 930 F.2d 1117, 1119 (5th  Cir. 1991).


33
In November 1997, Colgate served on Ms.  Kalis requests that she admit that (1)  she did not have any knowledge of the  substance of any written representations  on the packaging of the product; (2) she  had no knowledge of any documentation  provided with a container of Sterno  fondue fuel used in 1986; (3) she did not  possess a photograph of the container of  the Sterno fondue fuel that was used in  April 1986; and (4) her expert had never  examined the container in which the  Sterno fondue fuel was contained. Ms.  Kalis failed to respond to these  requests, and, therefore, according to  Rule 36, they were deemed admitted. Seven  months later, Ms. Kalis served a response  to the requests to admit that  incorporated Mrs. Kalis' recent memory  concerning the fondue fuel container.


34
"[T]he proper procedural vehicle through  which to attempt to withdraw admissions  made in these circumstances is a motion  under Rule 36(b) to withdraw admissions."  United States v. Kasuboski, 834 F.2d  1345, 1349 (7th Cir. 1987). Federal Rule  of Civil Procedure 36(b) provides in  relevant part that "[a]ny matter admitted  under this rule is conclusively  established unless the court on motion  permits withdrawal or amendment of the  admission." Fed. R. Civ. P. 36(b)  (emphasis added). Ms. Kalis never filed a  motion to withdraw admissions under Rule  36(b), and, therefore, the district  court's decision to strike her belated  answers to Colgate's requests was not an  abuse of discretion.


35
In sum, the district court did not abuse  its discretion in disregarding Mrs.  Kalis' affidavit or the belated answers  to the requests to admit. It further did  not abuse its discretion in denying Ms.  Kalis' additional discovery or in  declining to compel Colgate to answer  discovery requests when those issues were  not brought before the court in a timely  fashion. Without the additional documents  and discovery, Ms. Kalis cannot establish  a connection between Colgate and the  product that caused her injuries.  Consequently, the district court properly  entered summary judgment for Colgate.7


36
D. Magistrate Judge's Authority to Enter  Summary Judgment


37
Finally, Ms. Kalis argues that the  magistrate judge did not have the  authority to enter a summary judgment  order. We find this argument completely  devoid of merit. All parties signed a  consent form that indicated that, in  accordance with 28 U.S.C. sec. 636 and  Federal Rule of Civil Procedure 73, the  magistrate judge may conduct any and all  further proceedings, including trial and  entry of final judgment. See R.24.  Furthermore, the authorizing statute, 28  U.S.C. sec. 636(c), clearly allows a  magistrate judge to "conduct any or all  proceedings . . . and order the entry of  judgment" when all parties have  consented.8 Consequently, the  magistrate judge had the authority to  enter summary judgment.

Conclusion

38
For the foregoing reasons, we affirm the  judgment of the district court.

AFFIRMED


Notes:


1
 The claims against the other defendants are not  at issue in this appeal.


2
 Colgate manufactured Sterno-brand liquid fondue  fuel at the time Ms. Kalis suffered her injuries.


3
 Specifically, Ms. Kalis stated
In May 1998, plaintiff took a rule 30(b)(6)  deposition of a COLGATE witness. At that time,  COLGATE's attorney indicated that certain written  discovery served by plaintiff had not been re-  ceived by her. A copy of the written discovery  had been served on COLGATE in 1997. Another copy  was forwarded to COLGATE'S attorney weeks in  advance of the deposition. . . . This written  discovery should be answered. It is basic discov-  ery concerning the identity of the manufacturer  and distributors of the fuel and container. The  rule 30(b)(6) witness produced by COLGATE had not  searched COLGATE's records concerning issues in  the case, such as the identity of the firm which  distributed or sold Sterno in Chicago in 1986.  Those records should be searched. The COLGATE  rule 30(b)(6) witness identified others who have  or may have superior knowledge (to that of the  witness) concerning the manufacture and distribu-  tion of the fuel.
R.47 at 4.


4
 Specifically, Mrs. Kalis had testified that she  could not recall any details about the fuel  container (including its shape or its volume)  other than its height (8 to 9 inches) and its  color (yellow). She also testified that she could  not think of anything that would refresh her  recollection concerning the fuel container. See  R.69 at 7, 10.


5
 In her motion to stay briefing, Ms. Kalis also  argued that the Rule 30(b)(6) witness provided by  Colgate, James Lau, "had not searched COLGATE's  records concerning issues in the case, such as  the identity of the firm which distributed or  sold Sterno in Chicago in 1986. The records  should be searched. The COLGATE rule 30(b)(6)  witness identified others who have or may have  superior knowledge (to that of the witness)  concerning the manufacture and distribution of  the fuel." R.47 at 4. Although Ms. Kalis makes  vague references in her brief to the knowledge of  Colgate's 30(b)(6) witness (or lack thereof), she  does not argue that the trial court abused its  discretion by failing to grant additional 30(b)(-  6) discovery. See Appellant's Br. at 20. Indeed,  in the list of errors she assigns to the district  court, see Appellant's Br. at 8-9, she does not  mention any error with respect to the court's  failure to compel the 30(b)(6) witness to famil-  iarize himself with Colgate's records (assuming  that they existed). Because Ms. Kalis fails to  make a cogent argument on this point, supported  by relevant authority, this argument is waived.  See United States v. Berkowitz, 927 F.2d 1376,  1384 (7th Cir. 1991) ("We repeatedly have made  clear that perfunctory and undeveloped arguments,  and arguments that are unsupported by pertinent  authority, are waived (even where those arguments  raise constitutional issues).").
Furthermore, we do not understand Ms. Kalis to  be arguing that Colgate intentionally withheld a  more knowledgeable witness than that which it  produced. As stated above, Ms. Kalis' reference  in her brief to other persons named by Mr. Lau in  his deposition is not sufficient to escape waiver  under our precedent. Additionally, a review of  Mr. Lau's deposition testimony reveals that all  the individuals with greater knowledge on the  subject matter of the litigation were no longer  Colgate employees
a former marketing manager had  retired, and the remaining members of the manage-  ment team had left Colgate when it sold the  Sterno line in 1997. See R.74, Ex.F at 60-65.  Finally, even if we were convinced that Colgate  had withheld a more knowledgeable witness, we  could not lay all the blame with Colgate. Rule  30(b)(6) requires that the topics for the deposi-  tion be specified with "reasonable particulari-  ty." Ms. Kalis' generic Rule 30(b)(6) notice, see  R.74, Ex.D, does not meet this standard. See  Alexander v. Federal Bureau of Investigation, 188  F.R.D. 111, 114 (D.D.C. 1998) (rejecting notice  to depose on "any matters relevant to this case"  as not meeting the "reasonable particularity"  requirement); see also Prokosch v. Catalina  Lighting, Inc., 193 F.R.D. 633, 638 (D. Minn.  2000) ("[T]he requesting party must take care to  designate, with painstaking specificity, the  particular subject areas that are intended to be  questioned, and that are relevant to the issues  in dispute.").
Moreover, even if we did not believe that Ms.  Kalis had waived these arguments, we would be  reluctant to find that the district court abused  its discretion in denying additional Rule 30(b)(-  6) testimony. The district court was justified in  denying Ms. Kalis' request because she failed to  meet her burden under Rule 56(f) for securing  additional discovery in the face of a motion for  summary judgment. Federal Rule of Civil Procedure  56(f) states
Should it appear from the affidavits of a party  opposing the motion that the party cannot for  reasons stated present by affidavit facts essen-  tial to justify the party's opposition, the court  may refuse the application for judgment or may  order a continuance to permit affidavits to be  obtained or depositions to be taken or discovery  to be had or may make such other order as is  just.
"A party seeking the protection of Rule 56(f)  must make a good faith showing that it cannot  respond to the movant's affidavits. The rule  requires the filing of an affidavit stating the  reasons for a claimant's inability to submit the  necessary material to the court." United States  v. All Assets and Equip. of W. Side Bldg. Corp.,  58 F.3d 1181, 1190 (7th Cir. 1995) (citations and  footnote omitted). Although "[a] court may disre-  gard a failure to formally comply with Rule  56(f)," the opposing party's request for a con-  tinuance must "clearly set[ ] out the justifica-  tion for the continuance." Pfeil v. Rogers, 757  F.2d 850, 856 (7th Cir. 1985). "When a party  fails to secure discoverable evidence due to his  own lack of diligence," the necessary justifica-  tion is lacking, and "it is not an abuse of  discretion for the trial court to refuse to grant  a continuance to obtain such information." Id. at  857; see also Farmer v. Brennan, 81 F.3d 1444,  1449 (7th Cir. 1996) ("This Court has noted that  the party seeking further time to respond to a  summary judgment motion must give an adequate  explanation to the court of the reasons why the  extension is necessary.").
Ms. Kalis' motion to extend time did not meet  these requirements. First, Ms. Kalis' motion was  not supported by an affidavit. Second, although  Ms. Kalis mentioned in her motion that the Rule  30(b)(6) deposition was taken the month prior,  she offered the district court no explanation why  the Rule 30(b)(6) deposition was not conducted  within the discovery period. In the absence of a  reason from Ms. Kalis concerning the delay in the  Rule 30(b)(6) deposition, the district court was  entitled to conclude that the delay was due to  Ms. Kalis' lack of diligence. Consequently, the  district court did not abuse its discretion in  refusing her additional Rule 30(b)(6) discovery.  See Pfeil, 757 F.2d at 857 ("When a party fails  to secure discoverable evidence due to his own  lack of diligence, it is not an abuse of discre-  tion for the trial court to refuse to grant a  continuance to obtain such information.").
Additionally, although a specific time is not  stated in the rule, we believe that a party  needing additional discovery is under an obliga-  tion to bring the issue before the court in an  expeditious manner. Here, Ms. Kalis failed to  bring her motion to stay briefing and for addi-  tional discovery until three months after the  motion for summary judgment was filed and the  briefing schedule was set and one month after her  response was due. Under these circumstances, we  cannot fault the district court in denying Ms.  Kalis' motion.


6
 Specifically, Ms. Kalis' counsel states
"Please  confirm that you will provide answers to discov-  ery and produce a witness at the deposition  notwithstanding the discovery cutoff." R.74,  Ex.C.


7
 Ms. Kalis also maintains that the district court  erred in entering judgment on the alternative  ground that, under Illinois law, the absence of  the fondue fuel container is an absolute bar to  recovery. Because we have upheld the district  court's judgment on the first ground for summary  judgment, we have no occasion to reach the alter-  native ground.


8
 28 U.S.C. sec. 636 provides, in relevant part
(c) Notwithstanding any provision of law to the  contrary--
(1) Upon the consent of the parties, a full-  time United States magistrate . . . may conduct  any or all proceedings in a jury or nonjury civil  matter and order the entry of judgment in the  case, when specially designated to exercise such  jurisdiction by the district court or courts he  serves. . . .


