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3. G. R. Toshniwal and B. D. Pant, NATURE, 133, 947; 1934.
4. G. R. Toshniwal and B. D. Pant, see appendix of a paper read before the first meeting of the National Institute of Sciences on Jan. 8, 1935 (in the press).
5. R. R. Bajpai, Thesis for M.Sc. Examination. T. D. Bausal, Thesis for M.Sc. Examination.