1. Cf. Scientific Papers of the late Lord Rayleigh, Vol. III, Art. 142, Equation (74);Phil. Mag., 1887,24, 145.
2. Problems of Atomic Dynamics, by Max Born, 1926, p. 193.
3. Handbuch Der Physik, Zweite Auflage, Article by Max Born and M. Goppert-Mayer, 1933,24/2, p. 642.
4. P. G. N. Nayar,Proc. Ind. Acad. Sci., 1942,15, 293.