1. 1) British Standards Institution "Methods for crack opening displacement testing - COD- DD19". 1972.
2. 2) British Standards Institution "Methods for crack opening displacement (COD) testing", BS 5762, 1979.
3. 3) British Standard BS7448 part1 "Fracture Mechanics toughness tests Part1. Method for Determination of KIC, critical CTOD and critical J values of metallic materials", 1991.
4. 4) ASTM E1820: "Standard test method for crack-tip opening displacement CTOD fracture toughness measurement", American Society for Testing and Materials, Philadelphia, 1989.
5. 5) M. T. Kirk and Y-Y. Wang, in: Fatigue and Fracture Mechanics: 26th Volume, ASTM STP 1256, edited by W. G. Reuter, J. H. Underwood and J. C. Newman, Jr., American Society for Testing and Materials, Philadelphia, 1995, p.126.