1. ICFG International Cold Forging Group 1967–1992: Objectives, History, Published Documents. Meisenbach Verlag, Bamberg, Germany, pp. 33–82
2. ISO 1993 Steels for cold heading and cold extruding. ISO 4954, 2nd edn., p. 38
3. Tools—one of the mayor attributes for successful cold forging;Kuzman,1998
4. Handbook of Metal Forming;Lange,1985