1. C. R. Ward and A. S. Mann, Eighth Symposium on Line Pipe Research, Houston, Texas, Sept. 26–29, 1993, paper no. 21.
2. G. A. Alers and L. R. Burns, Mats. Eval. 45, 1184 (1987).
3. J.A. de Raad and J.v.d. Ent, Proceedings Twelfth World Conference on Non-Destructive Testing, eds. J. Boogaard and G.M. van Dijk (Elsevier B. V., Amsterdam, 1989), p. 156.
4. C. M. Fortunko, W. P. Dubé, and J. D. McColskey, Proceedings, IEEE 1993 Ultrasonics Symposium, Vol. 2, eds. M. Levy and B. R. McAvoy (IEEE, NY, 1993), p. 667.
5. J. A. Kleppe, Engineering Applications of Acoustics (Artech House, Norwood, MA, 1989), pp. 29–32.