1. I. M. Khalatnikov,An Introduction to the Theory of Superfluidity (Benjamin, New York, 1965); J. Wilks,The Properties of Liquid and Solid Helium (Clarendon Press, Oxford, 1967); D. R. Tilley and J. Tilley,Superfluidity and Superconductivity (Wiley, New York, 1974).
2. G. Rickayzen, inThe Helium Liquids, J. G. M. Armitage and I. E. Farquhar, eds. (Academic Press, New York, 1975).
3. J. D. Reppy and D. Depatie,Phys. Rev. Lett. 12, 187 (1964); J. S. Langer and J. D. Reppy, inProgress in Low Temperature Physics, VI, C. J. Gorter, ed. (North-Holland, Amsterdam, 1970).
4. G. B. Hess and W. M. Fairbank,Phys. Rev. Lett. 19, 216 (1967).
5. G. Emch,Algebraic Methods in Statistical Mechanics and Quantum Field Theory (Interscience, New York, 1972), p. 188.