References
- Abrikosov , A. A. , Gorkov , L. P. and Dzyaloshinski , I. E. 1963 . “ Methods of Quantum Field Theory in Statistical Physics ” . Englewood Cliffs : Prentice-Hall .
- Kadanoff , L. P. and Baym , G. 1962 . “ Quantum Statistical Mechanics Green's Function Methods in Equilibrium and Nonequilibrium Problems ” . In Frontiers in Physics , Vol. 8 , New York : W. A. Benjamin .
- Popov , V. N. 1987 . “ Functional Integrals and Collective Excitations ” . Cambridge University Press .
- Rivers , R. J. 1987 . “ Path Integral Methods in Quantum Field Theory ” . Cambridge University Press .
- Schulman , L. S. 1981 . Techniques and Applications of Path Integration , New York : Wiley .