1. S.P. Keeler, “Determination of Forming Limits in Automotive Stampings,” SAE Paper No. 650535, May 1985.
2. S. Hecker, “A Simple Technique for Determining Forming Limit Curves and Results on Aluminum Alloys,” Proc. 7th Biennal Congress of IDDRG, Amsterdam 1972, pp. 5.1–5.8.
3. R. Sowerby, E. Chu, and J.L. Duncan, “Determination of Large Strains in Metal Forming,”J. Strain Analysis, Vol. 7, 2, 1982, pp. 95–101.
4. R. Sowerby, N. Chandrasekaran, X. Chen, M.J. Rooks, and P. Correa, “The Development of Computer Aids for Sheet Metal Stampings,” Proc. III Intl. Conf. on CAD/CAM and FEM in Metal Forming, Stafford, U.K., Published by Pergamon Press, April, 1987, pp. 187–203.
5. S.P. Keeler, “Circle Grid Analysis (CGA),” a Report of Product Application Center, National Steel Corporation, Livonia, Michigan, 1986.