1. A. Ghozlan and E. Varoquaux Annales de Physique 4: 239 (1979)
2. C. Ebner and D. O. Edwards Physics Reports 2:77(1971)
3. G. Baym and C. J. Pethick in The Physics of Liquid and Solid Helium, part II ed. by K.H.Bennemann and J.B.Ketterson (Wiley, New York,1978)
4. E. P. Bashkin and A. E. Meyerovich Advances in Physics 30: 1, (1981)
5. I. N. Adamenko and V. I. Tsyganok, Zh.Eskp.Teor.Fiz. 87:865(1984)