1. K. Morigaki and M. Yoshida, Phil. Mag., in print.
2. Optical Effects in Amorphous Semiconductors;Tsai,1984
3. Optical Effects in Amorphous Semiconductors;Nakamura,1984
4. M. Kumeda, S. Ohzora, A. Morimoto, T. Shimizu, Y. Sano, M. Yoshida, I. Hirabayashi and K. Morigaki, unpublished.