1. W. M. Elsasser, Phys. Rev.,54, 126 (1938).
2. L. D. Kaplan, J. Meteorology,10, 2 (1953).
3. D. Q. Wark and M. Wolk, Monthly Weather Rev.,88, 7 (1960).
4. W. S. Seitz and D. V. Lundholm, JOSA,54, 315 (1964).
5. R. M. Goody, Atmospheric Radiation, Vol. 1 (Theoretical Basis), Oxford University Press, London, (1964), p. 412.