1. V. G. Khlopin and É. K. Gerling. Zh. obshch. khim.,6, No. 11, 1701 (1936).
2. V. G. Khlopin and M. L. Yashchenko, Izv. AN SSSR, seriya khim.,2, No. 3, 87 (1942).
3. J. Dobratz et al. Reporte, N-34, April, 9 (1943). Cited in the book by J. Katz and E. Rabinowich, The Chemistry of Uranium [Russian translation] Moscow, Foreign Literature Press, 1954.
4. A. Roberts. Reports, B-64, February, 6 (1942). Cited in the book by J. Katz and E. Rabinowich. The Chemistry of Uranium [Russian translation] Moscow, Foreign Literature Press, 1954.
5. N. P. Palei. Studies in Geology, Chemistry and Metallurgy. Reports of the Soviet Delegation to the International Conference on the Peaceful Uses of Atomic Energy (Geneva, 1955) [in Russian]. Moscow, Acad. Sci. USSR Press, 1955, p. 21.