1. 1) “The Global 2000 Report to the President”, U.S.A. Government Report (1977).
2. 2) “World Metal Demand Trends and Prospects”, Ed. by J. E. Tilton, Colorado School of Mines (1990).
3. 3) A. J. Cox, B. Nagel and K. Lawson: Factors Influencing Demand for Metals, Australian Bureau of Agricaltural and Resurce Economics, (1990).
4. 4) “Sekaino Base-Metal Shouhi Doukou Bunseki 2005”, Japan Oil, Gas and Metals National Corporation (2005).
5. 5) K. Halada, M. Shimada and K. Ijima: Mater. Trans. 49 (2008) 411–418.