1. Davidge, R.W., Tappin, G., Proc. Brith. Ceram. Soc. No. 15, 1970
2. Weiss, V., Notch Analysis of Fracture, Fracture Vol. III ed. by H. Liebowitz, Academic Press, New York and London, 1971
3. Neuber, H., Kernspannungslehre, Springer-Verlag, Ber1in-Göttin-gen-Heidelberg, 1958
4. Irwin, G.R., Proc, First Symposium on Naval Structural Mechanics, Pergamon Press, London and New York, N.Y. 1960