1. ArakiH., Publ. RIMS, Kyoto Univ. 11, 809 (1976); 13, 173 (1977).
2. BratteliO. and RobinsonD. W., Operator Algebras and Quantum Statistical Mechanics, Vol. 2, Springer-Verlag, N.Y., Heidelberg, Berlin, 1980.
3. ThirringW., A Course on Mathematical Physics, Vol. 4, Springer-Verlag, Vienna, N.Y., 1983.
4. DaviesE. B., Quantum Theory of Open Systems, Academic Press, London, N.Y., San Francisco, 1976.
5. StinespringW. F., Proc. AMS 6, 211 (1955).