1. Sze, S.M.: ‘Physics of semiconductor devices’, 2nd edn(Wiley New York USA 1981), p. 341
2. Gibbons, J.F.: ‘Semiconductor electronics’, (McGraw-Hill New York USA 1966), p. 353
3. Gray, P.E., and Searle, C.L.: ‘Electronic principles - physics, models and circuits’, (Wiley New York USA 1969), p. 47
4. Carroll, J.E.: ‘Physical models for semiconductor devices’, (Arnold London UK 1974), p. 39
5. The effect of small transverse dimensions on the operation of Gunn devices