this principle in a Title VII anti-retaliation claim). 91 . McDonnell Douglas Corp. v. Green, 411 U.S. 792, 93 S.Ct. 1817, 36 L.Ed.2d 668 (1973). 92 . See McGarry v. Bd. of County Comm'rs, 175 F.3d 1193, 1201 (10th Cir.1999); Lundien v. United Airlines, 242 F.3d 389, 2000 WL 1786579 (10th Cir.2000). 93 . McDonnell Douglas, 411 U.S. at 802, 93 S.Ct. 1817. 94 . Id. 95 . Id. at 804, 93 S.Ct. 1817. 96 . Kendrick, 220 F.3d at 1234; see also Anderson v. Coors Brewing Co., 181 F.3d 1171, 1178 (10th Cir.1999) (ADA); Sanchez v. Denver Pub. Sch., 164 F.3d 527, 533 (10th Cir. 1998) (ADEA). 97 . 42 U.S.C. § 2000e-3(a); see also 42 U.S.C. § 12203(b) (ADA); 29 U.S.C. § 623(d) (ADEA). 98 . See Sanchez, 164 F.3d at 532. 99 . See Gunnell v. Utah Valley State Coll., 152 F.3d 1253, 1265 (10th Cir.1998) (<HOLDING>). 100 . Burrus v. United Tel. Co. of Kan.,
holding that retaliatory discharge is a clearly established first amendment violation recognizing that a texas common law claim for retaliatory discharge is a claim sounding in tort recognizing the difference between statutory cause of action for retaliation and common law tort of retaliatory discharge recognizing the tort of retaliatory discharge holding that a retaliatory discharge claim must be predicated on intentional or knowing retaliation