1. I. S. Kainarskii, Zh. VKhO im. D. I. Mendeleeva,20, No. 2, 170?178 (1975).
2. N. I. Shirokov, Izv. Akad. Nauk SSSR, Met., No. 2, 102?104 (1973).
3. A. S. Berezhnoi, Multicomponent Systems of Oxides [in Russian], Naukova Dumka, Kiev (1970).
4. P. V. Gel'd and O. A. Esin, High-Temperature Reduction Processes [in Russian], Metallurgizdat, Sverdlovsk (1957).
5. N. A. Toropov, V. P. Barzakovskii, I. A. Bondar', and Yu. P. Udalov, Manual of the Phase Diagrams of Silicate Systems [in Russian], No. 2, Nauka, Leningrad (1970).