Ternay, A. L.; South, Bobbie E.; McKellar, R.; Lam, W. W.
Phosphorus, Sulfur and Silicon and the Related Elements, 1992 , vol. 73, # 1-4 p. 63 - 66

Hellwinkel, Dieter; Stahl, Heinz
Zeitschrift fuer Naturforschung, B: Chemical Sciences, 1993 , vol. 48, # 4 p. 521 - 538