1. A.L. Fetter, in The Physics of Liquid and Solid Helium, vol. I, ed. by K.H. Bennemann, J.B. Ketterson (Wiley, New York, 1976), p. 207
2. E.R. Dobbs, Helium Three (Oxford University Press, London, 2000)
3. A.I. Ahonen, J. Kokko, M.A. Paalanen, R.C. Richardson, W. Schoepe, Y. Takano, J. Low Temp. Phys. 30, 205 (1978)
4. A.C. Anderson, M. Kuchnir, J.C. Wheatley, Phys. Rev. 168, 2611 (1968)
5. M. Kuchnir, P.R. Roach, J.B. Ketterson, Phys. Rev. A 2, 262 (1970)