1. Iandelli and R. Ferro,Ann.Chim(Rome), 42,598–606(1952).
2. E.S. Makarov and VA. Levdik,KristaUografiya, l(6), 644–649 (1956) in Russian; TR:Sov. Phys. CrystaUogr., 1(6), 506–510 (1956).
3. K.H J. Buschow.J.Less-Common Met., 31,165–168(1973).
4. A. V. Andreev, KP. Belov, A. V Deryagin, Z A. Kazei, R.Z. Lev- itin, A. Monovsky, Yu.F. Popov, and VI. Silant’ev,Zh. Eksp. Tear. Fiz., 75, 2351–2361 (1978) in Russian; TO:Sov. Phys. JETP, 48,1187- 1193(1978).
5. D. Dayan, G. Kimmel, and M.P. Dariel,J. Nucl. Mater., 135,40- 45(1985).