1. Rustamov, P.G., Godzhaev, E.M., Guseinov, M.S., Aliev, O.M.: Zh. Neorg. Khim. 22 (1977) 540; Russ. J. Inorg. Chem. (English Transl.) 22 (1977) 298.
2. Godzhaev, E.M., Rustamov, P.G., Guseinov, M.S., Aliev, O.M.: Izv. Akad. Nauk SSSR, Neorg. Mater. 13 (1977) 624. Inorg. Mater. (USSR) (English Transl.) 13 (1977) 512.
3. Aliev, O.M., Rustamov, P.G.: Zh. Neorg. Khim. 23 (1978) 2800; Russ. J. Inorg. Chem. (English Transl.) 23 (1978) 1551.
4. Jayaraman, A.: Proc. of the 11th Rare Earth Res. Conf., Traverse City, Michigan 1974, p. 830 [Haschke, J.M., Eick, H.A. (eds.)].
5. Eliseev, A.A., Sadovskaya, O.S., Nguyen Van Tam: Izv. Akad. Nauk SSSR, Neorg. Mater. 11 (1975) 424; Inorg. Mater. (USSR) (English Transl.) 11 (1975) 361.