William F. Sanford v. Commissioner of Internal Revenue , 412 F.2d 201 ( 1969 )
Cohan v. Commissioner of Internal Revenue , 39 F.2d 540 ( 1930 )
Welch v. Helvering , 54 S. Ct. 8 ( 1933 )
Indopco, Inc. v. Commissioner , 112 S. Ct. 1039 ( 1992 )