1. F. J. PLANTEMA, ?Sandwich Construction? (John Wiley and Sons, New York, 1966).
2. A. NADAI, ?Theory of Flow and Fracture of Solids? Vol. 2, 2nd ed. (McGraw-Hill Book Co., New York, 1950) pp. 357?358.
3. C. W. BERT and M. KUMAR, University of Oklahoma, Contract N00014-78-C-0647, Report OU-AMNE-81-8 (July 1981).