1. E. H. Lieb and W. E. Thirring, Phys. Rev. Lett. 35,687(1975). See Phys. Rev. Lett. 35,1116 (1975) for errata.
2. M. S. Birman, Mat. Sb. 55(97), 125(1961); Amer. Mat. Soc. Translations Ser. 2, 53, 23 (1966).
3. J. Schwinger, Proc. Nat. Acad. Sci. 47, 122 (1961).
4. B. Simon, “Quantum Mechanics for Hamiltonians Defined as Quadratic Forms,” Princeton University Press. 1971.
5. B. Simon, “On the Number of Bound States of the Two Body Schrödinger Equation — A Review,” in this volume.