1. J.J. Loferski, J. Appl. Phys., 27, 777 (1956)
2. P. Rappaport, RCA Revue 20, 373 (1959)
3. C. Verie, M. Leroux, A. Tromson and P. Gibart, Proc. Int. Conf. Photovoltaic Solar En. Conf., Luxembourg, p. 1033 (1977)
4. E. Passaglia, Proc. 2nd European Symposium on Material Sciences in Space, Frascati (Italy), p. 391 (1976)
5. A. Nguyen Van Mau, G.Bougnot, M.Y. Muoy and G.M. Moussalli, See Ref.3, p. 405