1. P. L. Kapitza,Collected Papers of P. L. Kapitza, D. ter Haar, ed. (Pergamon Press, Oxford, 1965), Vol. II, p. 581.
2. J. Wilks,The Properties of Liquid and Solid Helium (Clarendon Press, Oxford, 1967).
3. T. H. K. Frederking, Chemical Engineering Progress Symposium Series (Advances in Cryogenic Heat Transfer)64, 21 (1968).
4. G. L. Pollock,Rev. Mod. Phys. 41, 48 (1969).
5. N. S. Snyder,Cryogenics 10, 89 (1970); see also N. S. Snyder,Natl. Bur. Stand. (U.S.) Tech. Note 385 (1969).