1. Baer, S., 1973, Chem. Phys.
1, 55.
2. Baer, S., 1974, J. Chem. Phys.
60, 435.
3. Longuet-Higgins, H.C., 1956, Proc. Roy. Soc. (London)
A235, 537; 1965, Disc. Faraday Soc.
40, 7.
4. Bloclv C., 1965, in Studies in Statistical Mechanics, Vol. HI, edited by J. de Boer and G.E. Uhlenbeck (North-Holland, Amsterdam ), Pt. A.
5. Baym, G., and Mermin, N.D., 1961, J. Math. Phys.
2, 232.