1. J. C. Jaeger:Elasticity, Fracture and Flow, 3rd Edition, Methuen, London, 1969.
2. J. J. Bikerman:Physical Surfaces, Academic Press, New York, 1970. See especially p. 203.
3. Lord Rayleigh:Philisophical Magazine, 1890, vol. 30, p. 386.
4. J. de Klerk:Physics Today, 1972, vol. 25, no. 11, p. 32.
5. W. M. Ewing, W. S. Jardotzky, and F. Press:Elastic Waves in Layered Media, McGraw-Hill, New York, 1957.