1. J.W. Strutt (Lord Rayleigh), The Theory of Sound, rev, ed. (Dover Publications, New York, 1945), pp, 117–118.
2. G. Sauerbrey, Z. Phy. 155: 206 (1959).
3. A. W. Warner and C.D. Stockbridge, in: Vacuum Microbalance Techniques, Vol. 2 ( Plenum Press, New York, 1962 ), p. 71.
4. W. P. Mason, private communication to A. W. W. (1932).
5. M. Onoe, Proc. IRE 45: 694 (1957).