1. M. Dumke, G. Heiserich, S. Franke, L. Schulz, and L. Overmeyer, J. Syst., Cybernet. Inform. 8, 55 (2010).
2. V. M. Andreev, B. V. Egorov, A. M. Koinova, V. M. Lantratov, and V. D. Rumyantsev, Sov. Phys. Semicond. 20, 275 (1986).
3. R. Pena and C. Algora, in Proceedings of the 20th EU Conference on Photovoltaic Solar Energy (Barcelona, Spain, 2005), p. 488.
4. G. A. Landis, J. Propuls. Power 8, 251 (1992).
5. J. Hecht, New Scientist 207 (2777), 25 (2010).