by: Rao, P.N.
by: James, P.S.B.R.
by: Sharma, K. K.
by: B. B. Kaliwal
by: Singh, Nirmal et al.
by: Smith, M.A.
by: Distant, W.L.
by: M. H. Khan, Vikram R., Perumal P. Abhijit Mitra
by: Srivastava, R.