1. anon 1953, Tow way press, Steel, vol.63, no.2, pp66-69.
2. anon 1967, Forging on a multiple-ram press, Metal Forming, vol.34, no.7, pp199-204.
3. anon 1970, Injection forging presses, Metal Forming, vol.37, no.3, pp74-77.
4. The Mathematical Theory of Plasticity;Hill,1950
5. Johnson, W. & Mellor, P.B. 1973, Plasticity for Mechanical Engineers.