1. G.E. Uhlenbeck, these proceedings.
2. J.R. Dorfman, these proceedings.
3. See a)N.N. Bogolubov in Studies in Statistical Mechanics, Vol. I, (J. de Boer and G.E. Uhlenbeck eds.), North-Holland Publishing Company, Amsterdam, 1962, p. 5
4. b) G.E. Uhlenbeck and G.W. Ford in Lectures in Applied Mathematics, Vol. I, Amer. Math. Soc., Providence, 1963, Ch. 7.
5. a) E.G.D. Cohen, Physica 28, 1025 (1962)