1. P. Pascal, Nouveau Traite de Chimie Minerale, Tome II, Masson, Paris, 1966, p. 702.
2. Preparation and Properties of Ferrospinels Containing Ni3+
3. N. Yoji, M. Kimio, Patent, Japan, Kokai, Tokyo Koho, 79,159,696 (Cl.Ho1F1/34), 17 Dec. 1979, Appl. 78/68, 682.