F. K. Volynets and L. V. Udalova, Izv. Akad. Nauk SSSR, Neorg. Mater.,8, No. 2, 285 (1972).
L. V. Udalova, L. I. Kleshchinskii, G. N. Vanyukhin, and L. A. Kiseleva, Izv. Akad. Nauk SSSR, Neorg. Mater.,15, No. 5, 1654 (1979).
U.S.A. Patent, No. 3974249.
H. Winchell, Optical Properties of Minerals, Academic Press (1965).
J. C. Wurst and J. A. Nelson, J. Am. Ceram. Soc.,55, 109 (1972).
J. Dorn, Creep and Return [Russian translation], Moscow (1961).
A. L. Stuijts, Ann. Rev. Mater. Sci.,3, 393 (1973).
P. Murrey, E. P. Rodgers, and A. E. Williams, Trans. Brit. Ceram. Soc.,53, No. 8, 476 (1954).
W. D. Kingery, J. H. Woulbroun, and F. R. Charvart, J. Am. Ceram. Soc.,46, No. 8, 391 (1963).