it with pertinent authority. We therefore deem this argument waived pursuant to Federal Rule of Appellate Procedure 28(a)(3) & (a)(6). See Thomas & Betts Corp. v. Panduit Corp., 138 F.3d 277, 301 (7th Cir.), cert. denied,-U.S.-, 119 S.Ct. 336,-L.Ed.2d -(1998) (No. 98-179); see also United States v. Berkowitz, 927 F.2d 1376, 1384 (7th Cir.1991) (stating that ”[w]e repeatedly have made clear that perfunctory and undeveloped arguments, and arguments that are unsupported by pertinent authority, are waived”), cert. denied, 502 U.S. 845, , Main & Co., 996 F.2d 1534, 1539 (3d Cir.1993) (stating that "[s]imply because one provides goods or services that ultimately benefit the enterprise does not mean that one becomes liable under RICO”); Nolte v. Pearson, 994 F.2d 1311, 1317 (8th Cir.1993) (<HOLDING>); Redtail Leasing, Inc. v. Bellezza, No. 95
holding even though experts are permitted to give an opinion they may not offer an opinion regarding the credibility of others holding that false arrest and false imprisonment claim were not duplicative holding that to prevail under civil rico plaintiff must prove that defendants participated in the conduct of an enterprise through a pattern of racketeering activity holding that attorneys who prepared allegedly false opinion letters and informational memoranda regarding a music recording leasing program had not participated in operation or management of enterprise holding that the chief financial officer of a hospital had sufficient access to the allegedly false cost reports resulting from the false invoices to require him to plead at least one example of a false claim with particularity