1. P. Hoeller, W. Gebhardt, and W. Mueller,Materialpruefung 22:32 (1980) (in German).
2. G. J. Gruber, Development of relationships between defect characteristics and signal parameters, Final Report 17-9210, Southwest Research Institute, San Antonio, Tex. (1979).
3. B. T. Khuri-Yakub, G. S. Kino, and Y. Murakami, Ultrasonic wave scattering for defect characterization applied to ceramic materials, Paper presented at 38th American Society for Nondestructive Testing Conference, Denver, Colo., October (1978).
4. A. Freedman,Acustica 12:61 (1962).
5. A. Freedman,Acustica 12:10 (1962).