1. W. Schultz, Rekombinations-und Generationsprozesse in Halbleitern. Halbleiterprobleme, Vol. 5. Lecture given in 1965.
2. P. T. Landsberg, Semiconductors and Phosphors (Braunschweig: Vieweg and Son, 1958). Lecture given in 1956.
3. P. T. Landsberg, Solid state physics in electronics and telecommunications (London: Academic Press, 1960). Vol. 1, p. 436. Lecture given in 1958.
4. P. T. Landsberg, Proc. I. E. E. 106, Supp.. B 17, 908 (1959). Lecture given in 1959.
5. R. N. Hall, Proc. I. E. E. 106. Suppl. B 17, 923 (1959). Lecture given in 1959.