Aspelund
Acta Academiae Aboensis, Series B: Mathematica et Physica, 1939 , vol. 12, # 2 p. 7,26
Chem.Abstr., 1943 , p. 6251
Chem. Zentralbl., 1942 , vol. 113, # II p. 1120

Aspelund
Acta Academiae Aboensis, Series B: Mathematica et Physica, 1939 , vol. 12, # 5 p. 6,20
Chem.Abstr., 1947 , p. 2413
Chem. Zentralbl., 1942 , vol. 113, # II p. 1122