1. British Standards, Methods for crack opening displacement (COD) testing, BS 5762 (1979).
2. AS 2205.7.3, Crack opening displacement (COD) test, Standards Association of Australia (1983).
3. Chinese Standard, Crack opening displacement (COD) testing method, GB 2358-80 (1980).
4. ASTM E813-83, Standard test for J 1c a measure of fracture toughness.
5. Chinese Standard, Test method for determining ductile fracture toughness of metals by use of J R resistance curve, GB 2038-80 (1980).