1. M. Kato, Method of Manufacture of A Magnetic Rotor Core Member for A Dynamoelectric Machine, United States Patent, 4759117[P], Ibaragi, 26 July 1988
2. A.E. Goffart, Process for Manufacturing Alternator Pole Piece, United States Patent, 5429687[P], 4 July 1995
3. T. Awano, Y. Oishi, Process for Making a Flanged Metal Product Having Raised Portions Around Its Flange, United States Patent, 3769696[P], 6 Nov 1973.
4. E. Körner and R. Knödler, Possibilities of Warm Extrusion in Combination with Cold Extrusion, J. Mater. Process. Technol., 1992, 35, p 451–465
5. M.C. Lee, S.H. Chung, S.M. Jang, and M.S. Joun, Three-Dimensional Simulation of Forging Using Tetrahedral and Hexahedral Elements, Finite Elem. Anal. Des., 2009, 45, p 745–754