1. Wells, A.A.: Application of fracture mechanics at and beyond general yield, British Welding Journal, 1963, pp. 563–570.
2. Wells, A.A.: Crack opening displacements from elastic-plastic analyses of externally notched tension bars, Engineering Fracture Mechanics, 1969, Vol. 1, pp. 399–410.
3. BS 5762:1979. Methods for crack opening displacement (COD) testing. The British Standards Institution.
4. Hellmann,D., and K.H. Schwalbe: On the experimental determination of CTOD-based R-curves, this workshop.
5. Hellmann, D.,and K.-H. Schwalbe: Geometry and size effects on JR and δR-curves under plane stress conditions, in: ASTM STP 833, 1984, pp. 577–605.