1. H. U. Harten, Z. Phys.,126, Nos. 7?9, 619 (1949).
2. M. A. Élango, Tr. IFA Akad. Nauk EstSSR,17, 135 (1961);21, 215 (1962).
3. P. G. Harrison, J. Chem. Phys.,37, No. 2, 388 (1962); Phys. Rev.,131, 2505 (1963).
4. S. M. Malaev, Abstract of Candidate's Dissertation [in Russian], Tomsk (1971).
5. P. E. Deryabin, V. V. Timofeev and T. V. Gubareva, Sb. KuzPI, No. 52, Kemerovo (1972).