by Singh, Malkiat, Gurm, H. S., Deshpande, M. R., Rastogi, R. G., Sethia, G., Jain, A. R., Janve, A. V., Rai, R. K., Patwari, V. M., Subbarao, B. S.
Published in Journal of Earth System Science (01.03.1978)

by Rao, P V, Mangala, A, Rao, B S, Prakash, K M
Published in Experientia (15.10.1977)