1. 1) U.S. Department of Energy: Fuel Cells, Technical Plan, Multi-Year Research, Development and Demonstration Plan, (2007).
2. 2) A. Inoue, T. Aoki and H. Kimura: Mater. Trans., JIM 38 (1997) 175–178.
3. 3) F. A. Lewis: The Palladium Hydrogen System, (Academic Press, London 1967) p. 11.
4. 4) M. Okada: Kinzokuzairyo no Kagaku, (The Nikkan Kogyo Shimbun Ltd. 1992) p. 108.
5. 5) A. Inoue: Acta Mater. 48 (2000) 279–306.