Knetsch v. United States , 81 S. Ct. 132 ( 1960 )
Grodt & McKay Realty, Inc. v. Commissioner , 77 T.C. 1221 ( 1981 )
Gregory v. Helvering , 55 S. Ct. 266 ( 1935 )
Commissioner v. Tufts , 103 S. Ct. 1826 ( 1983 )