1. F. Morse and G. Fishbach, Methods of Theoretical Physics [Russian translation], Vol. 1, IL, Moscow (1978).
2. Yu. N. Podil'chuk, ?Stress state of a transversely isotropic medium with a parabolic crack?, Prikl. Mekh.,30, No. 7, 3?8 (1994).
3. M. P. Savruk, Fracture Mechanics and the Strength of Materials. Handbook [in Russian], Vol. 2, Kiev (1988).
4. H. A. Elliot, ?Three-dimensional stress distributions in hexagonal aeolotropic crystals?, Proc. Cambridge Philos. Soc.,44, No. 4, 522?533 (1948).
5. M. K. Kassir and G. C. Sih, Three-Dimensional Crack Problems, Noordhoff Int. Publ., London (1975).