1. A.W. Blakes, in: U. Rössler (Ed.), Festkörperprobleme/Advances in Solid State Physics, Vol. 30, Vieweg, Braunschweig, 1990, p. 403.
2. J. Werner, R. Bergmann, R. Brendel, in: R. Helbig (Ed.), Festkörperprobleme/Advances in Solid State Physics, Vol. 34, Vieweg, Braunschweig, 1994, pp. 115–146.
3. H. Naomoto, S. Hamamoto, A. Takami, S. Arimoto, T. Ishihara, H. Kumabe, T. Murotani, S. Mitsui, in: Tech. Digest 7th Int. Photovoltaic Sci. Eng. Conf., 1993, p. 79.
4. S. Arimoto, H. Morikawa, M. Deguchi, Y. Kawama, Y. Matsuno, T. Ishihara, H. Kumabe, T. Murotani, S. Mitsui, in: Tech. Digest 7th Int. Photovoltaic Sci. Eng. Conf., 1993, p. 103.
5. H. v. Campe, B. Cembolista, H. Ebinger, W. Hoffmann, U. Huth, W. Warzawa, W. Warta, in: L. Guimaräes, W. Palz, C. der Reyff, H. Kiess, P. Helm (Eds.), Proc. 11th E.C. Photovoltaic Solar Energy Conf., Harwood Academic, Chur, 1993, p. 1066.