1. Understanding sheet metal formability;Keeler;Machinery,1968
2. Circular grid system—a valuable aid for evaluating sheet metal formability;Keeler;SAE Paper No. 680092,1968
3. Plastic instability and fracture in sheets stretched over rigid punches;Keeler;Trans. ASM,1963
4. Applications of strain analysis to sheet metal forming problems in the press shop;Goodwin;SAE Paper No. 680093,1968
5. Formability of high-strength low-allow steel sheets;Hecker;Met. Engng Quart.,1973