1. 1) A.Moriya, A.Kanai: Journal of MMIJ, 109 (1993), 1164-1169.
2. 2) Japan Aircraft Development Corporation: Worldwide Market Forecast for Commercial Air Transport (2006), 2006-2025.
3. 3) H.Ichihashi: Metal, 73(2003), 417.
4. 4) S.Nakamura: Industrial rare metal, 122(2006), 66.
5. 5) J.Nanjo: The JAPAN TITANIUM SOCIETY Text of Titanium workshops, 13(2006), 15-29.