Quantum statistical mechanics : Green's function methods in equilibrium and nonequilibrium problems / Leo P. Kadanoff, Gordon Baym. Kadanoff, Leo P. Baym, Gordon, joint author. Statistical mechanics. Quantum theory. QC175.3 .K3 530.13 KAQ New York : W.A. Benjamin, 1962. 1962. 1962 Text xi, 203 p. : eng Frontiers in physics