1. ASTM E 399-83, Standard Test Method for Plane-Strain Fracture Toughness of Metallic Materials, 1983.
2. ASTM E 1304-89, Standard Test Method for Plane-Strain (Chevron Notch) Fracture Toughness of Metallic Materials, 1989.
3. ASTM E 813-88, Standard Test Method for JIC, a Measure of Fracture Toughness, 1988.
4. Astiz, M. A., PhD thesis, Universidad Politécnica de Madrid, Escuela de Ingenieros de Caminos, 1976.
5. An incompatible singular elastic element for two- and three-dimensional crack problems