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3. M. I. Petrashen; and E. D. Trifonov, The Use of Group Theory in Quantum Mechanics [in Russian], Nauka, Moscow (1967), p. 307.
4. D. A. Bochyar, N. P. Gambaryan, É. M. Broinina, and R. Kh. Freidlina, Dokl. Akad. Nauk SSSR,183, No. 6, 1324 (1968).
5. D. A. Bochvar and N. P. Gambaryan, in: Types of Organometallic Compounds of the Transition Metals [in Russian], Nauka, Moscow (1975), Book 1, pp. 9?21. (Methods of Hetero-organic Chemistry).