1. Brown, W. F., and Srawley, J. E., ASTM STP 410 (American Society for Testing and Materials, Philadelphia, 1966).
2. Williams, J. G., and Isherwood, D. P., J. Strain Anal., 3(1), 17 (1968).
3. Paris, P. C., and Sih, G. C., ASTM STP 381 (American Society for Testing and Materials, Philadelphia, 1965).