By Ghosh, J.K., Ramamoorthi, R.V.
By Franks, R.V.
By Burton, Maurice, Assen, R.V., Assen, Rob Van, etc.
By Melville, R.V., British Geological Survey
By Ivchenko, I.N., Loyalka, S.K., Tompson Jr., R.V.
By Oech, R.V.
By Cohen, R.V., Aun, F., Uip, D.E.
By Collier, R.V.