1. 1) Grill, Roberts, Johnotin, George "Tool Steel" (1946) p 381
2. 2) Materials & Methods 36 (1952) p.114
3. 3) SAE Handbook(1952) p.126
4. 5) J.O. Ward, M.D. Jepson, J.R. Rait: J. Iron & Steel Inst. 175 (1952) p. 1
5. 6) John L. Everhart: Materials & Methods 37 (1953) p. 115