1. See the classic papers by L. Landau and R. Peierls,Z. Phys. 69, 56–69 (1931); N. Bohr and L. Rosenfeld,Mat. Fys. Medd. Dan. Vid. Selsk. 12, no. 8 (1933) and N. Bohr and L. Rosenfeld,Phys. Rev. 78, 794–798 (1950); these papers are reprinted and commented on in J. A. Wheeler and W. H. Zurek, eds.,Quantum Theory and Measurement (Princeton University Press, Princeton, 1983).
2. D. Bohm,Quantum Theory (Prentice-Hall, Englewood Cliffs, 1951).
3. See, e.g., W. H. Louisell,Quantum Statistical Properties of Radiation (Wiley, New York, 1973), or in M. Sargent, M. O. Scully, and W. E. Lamb, Jr.,Laser Physics (Addison-Wesley, Reading, 1974).
4. G. Szegö,Orthogonal Polynomials (American Mathematical Society, New York, 1939).
5. See, e.g., M. Born, Vorlesungen über Atommechanik, inStruktur der Materie in Einzeldarstellungen, M. Born and J. Franck, eds. (Springer, Berlin, 1925); P. Debye,Physik. Z. 28, 170–174 (1927).