1. P. I. Vincent, in ?Encyclopedia of Polymer Science and Technology?, Vol. 7 (John Wiley, New York, 1967) p. 292.
2. J. G. Williams, ?Fracture Mechanics of Polymers?, Chap 6 (John Wiley, New York, 1984).
3. H. H. Kausch andJ. G. Williams, in ?Encyclopedia of Polymer Science and Engineering?, Vol. 6, 2nd Edn. (John Wiley, New York, 1986).
4. R. Seldon,Polym. Testing 7 (1987) 209.
5. L. H. Lee, J. F. Mandell andF. J. McGarry,Polym. Eng. Sci. 27(15) (1987) 1128.