1. Zhang, L., and Luck, R., Metallkde, 2003, vol. 94, no. 2, p. 108.
2. Gratias, D., Calvayrac, Y., Devaud-Rzepski, J., and Faudot, F., Non-Crystal. Sol., 1993, vols. 153–154, p. 482.
3. Faudot, F., Ann. Chim.Fr., 1993, vol. 18, p. 445.
4. Prevarskii, A.M., Izv. AN SSSR, Metally, 1971, no. 4, p. 220.
5. Omarov, L.K., Smauglov, D.U., Askarov, M.S., and Alekseeva, G.K., Vesti AN KazSSR, 1985, no. 5, p. 10.