1. A. I. Fomin,Sov. Phys. JETP 34, 1371 (1972).
2. K. H. Bennemann and J. B. Ketterson,The Physics of Liquid and Solid Helium, Part II (Wiley, New York, 1978).
3. I. L. Bekarevich and I. M. Khalatnikov,Sov. Phys. JETP 12, 1187 (1961).
4. J. C. Wheatley,Rev. Mod. Phys. 47, 467 (1975).
5. S. A. Bogacz and J. B. Ketterson,Bull. Am. Phys. Soc. 29, 681 (1984).