1. Rapid Fabrication Methods for Sheet Metal Forming Dies;Walczyk,1996
2. Spring-Forming Device;Williams,1923
3. Press;Walters,1943
4. A Preliminary Study of an Infinitely Variable Surface Generator and Its Application to Die Forming;Wolak;Mfg. Engg. Trans.,1973
5. Apparatus for Forming Sheet Metal;Pinson,1980