Helvering v. Pfeiffer , 58 S. Ct. 159 ( 1937 )
Helvering v. Griffiths , 63 S. Ct. 636 ( 1943 )
Helvering v. Gowran , 58 S. Ct. 154 ( 1937 )
Koshland v. Helvering , 56 S. Ct. 767 ( 1936 )