1. K. F. Herzfeld and T. A. Litovitz, Absorption and Dispersion of Ultrasonic Waves, Academic Press, Inc., New York (1959), Chap. 7.
2. T. L. Cottrell and J. C. McCoubrey, Molecular Energy Transfer in Gases, Butterworth & Co. (Publishers) Ltd., London (1961), Chap. 6.
3. K. F. Herzfeld, Fundamental physics of matter, in: Thermodynamics and Physics of Matter, F. D. Rossini, ed., Princeton University Press, Princeton, N. J. (1965), Sec. H, pp. 111–239.
4. N. F. Mott and H. S. W. Massey, The Theory of Atomic Collisions, 3rd ed., Oxford University Press, Inc., New York (1965).
5. B. Stevens, “Collisional Activation in Gases,” in: International Encyclopedia of Physical Chemistry and Chemical Physics, Vol. 3, Topic 19, Pergamon Press, Inc., Elmsford, N. Y. (1967).