1. T. Nakagawa and T. Maeda. Billet production by clamp shearing method. Preprint 4th Int. Cold Forging Conf., Düsseldorf. 1970. p. 351.
2. T. Nakagawa and K. Miyamoto. Tool-life test in clamp shearing of steel bar and wire. Proc. 12th Int. MTDR Conf. 1971, p. 567.