1. See, for example,B. d’Espagnat, Editor:Foundations of Quantum Mechanics (New York, N. Y., 1971).
2. A revew of the field was given byM. Surdin:Ann. Inst. Poincaré,15, 203 (1971). New developments and further references can be seen inE. Santos:Lett. Nuovo Cimento,4, 497 (1972);Nuovo Cimento,19 B, 57 (1974).
3. H. G. Hall andR. E. Collins:Journ. Math. Phys.,12, 100 (1971), and references therein.
4. See, for example,O. E. Lanford III: inStatistical Mechanics and Quantum Field Theory, edited byC. DeWitt andR. Stora (New York, N. Y., 1971), p. 141.
5. See ref. (4), See, for example,O. E. Lanford III: inStatistical Mechanics and Quantum Field Theory, edited byC. DeWitt andR. Stora (New York, N. Y., 1971), p. 159.