1. W.F. Kuhs, R. Nitsche, K. Scheunemann, Mater. Res. Bull. 14 (1979) 241.
2. I.P. Studenyak, V.O. Stefanovich, M. Kranjcec, D.I. Desnica, Yu.M. Azhnyuk, Gy.Sh. Kovacs, V.V. Panko, Solid State Ionics 95 (1997) 221.
3. I.P. Studenyak, Gy.Sh. Kovacs, B.I. Zinzikov, A.N. Borets, Fiz. Tverd. Tela 29 (1987) 3442.
4. I.P. Studenyak, Gy.Sh. Kovacs, A.S. Orliukas, Ye.T. Kovacs, Izv. AN: Ser. Fiz. 56 (1992) 86.
5. I.P. Studenyak, M. Kranjcec, Gy.S. Kovacs, V.V. Panko, I.D. Desnica, A.G. Slivka, P.P. Guranich, J. Phys. Chem. Solids 60 (1999) 1897.