1. Alfey, T., Mechanical Behavior of High Polymers, Interscience Publishers, Inc., New York (1948).
2. Coolidge, D. J., Jr., “An Investigation of the Mechanical and Stress-Optical Properties of Columbia Resin, CR-39,” Proc. SESA, 74–82 (1948).
3. Frocht, M. M., Protoelasticity,I and II,John Wiley & Sons, Inc.,New York (1941).
4. Hiltscher, R., “Spannungsgoptische Untersuchung elastoplasticher Spannungszustande,” ZVDI,95 (23) (1953).
5. Kiesling, E. W., “Nonlinear, Quasi-Static Behavior of Some Photoelastic and Mechanical Model Materials,” PhD dissertation, College of Engineering, Michigan State University (1966).