Singh, P. K.; Singh, H. B.; Tandon, J. P., Indian Journal of Chemistry, Section A: Inorganic, Physical, Theoretical and Analytical, 1981, vol. 20, # 2, p. 202 - 203
Singh, P. K.; Singh, H. B.; Tandon, J. P., Indian Journal of Chemistry, Section A: Inorganic, Physical, Theoretical and Analytical, 1981, vol. 20, # 2, p. 202 - 203