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2. Shadow optical method of caustics;Kalthoff,1987
3. Optical theory of caustics;Kim,1989
4. Two optical techniques sensitive to gradients of optical path difference: the method of caustics and the coherent gradient sensor (CGS);Rosakis,1993
5. Singular behavior at the end of a tensile crack in a hardening material;Hutchinson;Journal of the Mechanics and Physics of Solids,1968