1. V. V. Vargin, The Manufacture of Colored Glass [in Russian], Lenprom, Moscow-Leningrad (1940).
2. W. A. Weyl, Coloured Glasses, Society of Glass Technology, Sheffield (1951).
3. D. G. Galimov, K. D. Tarzimanov, N. R. Yafaev, A. I. Neich, and L. S. Semina, Fiz. Khim. Stekla,2, No. 5, 392 (1976).
4. A. Paul, J. Mater. Sci.,10, 415 (1975).
5. G. B. Abdullaev, N. I. Ibragimov, Sh. V. Mamedov, T. I. Dzhurvaly, and G. M. Aliev, Dokl. Akad. Nauk AzerbSSR,20, 13 (1964).