1. N.D. Patel, J. Van den Andel, and P.S. Nicholson, Review of Progress in Quantitative Nondestructive Evaluation, edited by D.O. Thompson and D.E Chimenti (Plenum Press, New York, 1987), pp. 663–670.
2. N.D. Patel, A. Gryzmek and P.S. Nicholson, to be published.