1. K. KUBO and Y. HIRAI: Proc. 26th Joint Conf. on Technology of Plasticity, Kyoto, Japan, Japan Society for Technology of Plasticity and Japan Society of Mechanical Engineers, 1975, 393–395.
2. E. STEBEL: 'Die Formgebung im bildsamen Zustand'; 1932, Düsseldorf, Verlag Stahleisen.