1. G. W. Mackey:The Mathematical Foundations of Quantum Mechanics, A Lecture- Note Volume (New York, N. Y., etc., 1963). See further M. A. Neumark :Normierte Algebren (Berlin, 1959);G. A. Pozzi:Nuovo Cimento, Suppl., Serie I,4, 37 (1966).
2. G. Ludwig:An Axiomatic Basis for Quantum Mechanics (Berlin, etc., 1985). See also K. Kraus :States, Effects and Operations, Lecture Notes in Physics, Vol.190 (Berlin, etc., 1983).
3. K. Kraus : in the volumeThe Uncertainty Principle and Foundations of Quantum Mechanics, edited by W. C. Pryce and S. S. Chiswick (London, etc., 1977), p. 293 ;A. Barchielli,L. Lanz andG. M. Peosperi :Proceedings of the International Symposium on the Foundations of Quantum Mechanics (Tokyo, 1983), p. 165;G. M. Prosperi:Proceedings of the Conference on Information Complexity and Control in Quantum Physics, in course of publication;L. Lanz andO. Melsheimer:Observables in the Confined Systems, in preparation.
4. W. Pauli:General Principles of Quantum Mechanics (Berlin, etc., 1980). This is an English translation (not very accurate) of the fundamentalHandbuch article (1933 and 1958).
5. A. Sommerfeld :Atombau und Spektrallinien, Bd. 2, Zweite Auflage (Braunschweig, 1951).