1. Y. Pao, W. Sachse and H. Fukuoka in Physical Acoustics Vol. XVII, Academic Press, 1984.
2. J.S. Heyman, S.G. Allison, K. Salama, and S.L. Chu, Symposium on NDE, Applications to Materials Processing, edited by O. Buck and S. Wolf, p. 177, 1983.
3. J.H. Cantrell, W.T. Yost, S. Razvi, P. Li and K. Salama, Proc. IEEE Ultrasonics Symposium 1986, p. 1075.
4. K. Brugger, Physical Review, 133 A, p. 1611, 1964.
5. J.H. Cantrell, Physical Review, B21, p. 4191, 1980.