Parfent'ew; Schamschurin Trudy Uzbeksk.Univ.Sbornik Rabot Chim.Chem.Abstr., 1939 , vol. 15, p. 67,72 Trudy Uzbeksk.Univ.Sbornik Rabot Chim.Chem.Abstr., 1941 , p. 4351