1. C. N. Yang, Rev. Mod. Physics 34, 694–704 (1962).
2. O. Penrose, Phil. Mag. 42, 1373–1377 (1951); O. Penrose and L. Onsager, Phys. Rev. 104, 576-584 (1954).
3. F. London, Nature, 141, 643 (1938); Phys. Rev. 54,947 (1938).
4. The search for the B-E condensate has been vigorously pursued for over fifty years. It has almost taken on the character of the Scarlet Pimpernel, of whom it was written: “They seek him here, they seek him there, is he in heaven, is he in hell, the damned elusive Pimpernel?” None the less, in the last few years there seems to have developed a consensus that a condensate exists with n 0 equal approximately to 10%. This value was obtained, for example, in the careful and innovative paper of T. R. Sosnick, W. M. Snow and P. E. Sokol. Physical Review B, 41, 11,185 (1990). In a more recent paper, Europhysics Letters, 19, 403 (1992), Snow, and Sokol, together with Y. Wang, lament that “A quantitative microscopic theory which relates n 0 to most of the measured thermodynamic and transport properties of the superfluid does not exist”.
5. Felix Bloch, Phys. Rev. A, 137,787 (1965).