1. E.M. Conwell, High Field Transport in Semiconductors, Academic Press, New York and London, 1967.
2. J.E. Caroll, Hot Electron Microwave Generators, London 1970
3. M.E. Levinstein, Yu.K. Pozhela and M.S. Shur, The Gunn Effect, 1975 (in Russian).
4. J.E. Smith, M.I. Nathan, J.C. McGroddy and S.A. Porowski, Appl. Phys. Lett., 15, 242, (1969).
5. M. Rodot, Proc. X Intern. Conf. Phys. Semicond. Moscow, Nauka 1968, p. 639.