Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc. , 104 S. Ct. 2778 ( 1984 )
Celotex Corp. v. Catrett, Administratrix of the Estate of Catrett , 106 S. Ct. 2548 ( 1986 )
Welch v. Helvering , 54 S. Ct. 8 ( 1933 )