1) H. Tsuru and T. Nakagawa: "Development and Future of the Electric 6 Axle CNC Powder Forming Press", Production Research, 43 (1991) 528-536.
2) C. Tsumuki, I. Nagare, T. Hikosaka and T. Iwama: "Development of Powder Forged Connecting Rods", Toyota Technical Review, 33 (1983) 173-179.
3) T. Takahashi, T. Chikada, A Manabe, G. Fukuda and Y. Fujiwara: "Strengthening of Sintered Ferrous Materials without Heat Treatment", Toyota Technical Review, 38 (1988) 222-229.
4) H. G. Rutz and F. G. Hanejco: "high Density Processing of High Performance Ferrous Materials", The Int. J. of Powder Metallurgy, 31 (1995) 9-17.