McDonnell Douglas Corp. v. Green , 93 S. Ct. 1817 ( 1973 )
Anderson v. Liberty Lobby, Inc. , 106 S. Ct. 2505 ( 1986 )
Celotex Corp. v. Catrett, Administratrix of the Estate of Catrett , 106 S. Ct. 2548 ( 1986 )