1. Hadeler KP (1964a) An estimate for the spectrum of normal operators (Russian). Dokl Akad Nauk SSSR 157: 284 –287 (trans. (1964) Sov Math Dokl 5:944–947)
2. Hadeler KP (1964b) On the spectrum of normal operators and of their perturbations (Russian). Dokl Akad Nauk SSSR 158: 1042–1043 (trans. (1965) Sov Math Dokl 5:1371–1372)
3. Hadeler KP (1973) Selektionsmodelle in der Populationsgenetik. In: Brosowski B, Martensen E (eds) Methoden und verfahren der mathematischen physik, vol 9. Bibliographisches Institut, Mannheim, pp 137–160
4. Hadeler KP (1974a) Mathematik für Biologen (trans. (1982) Matemáticas para Biólogos (Spanish). Editorial Reverté, Barcelona). Springer, Berlin
5. Hadeler KP (1974b) On the theory of lateral inhibition. Kybernetik 14:161–165