1. 1) F. C. Walsh and R. G. A. Wills, Electrochim. Acta, 55, 6342 (2010).
2. 2) A. Ishihara, M. Hamazaki, H. Imai, M. Matsumoto, Y. Kohno, K. Matsuzawa, S. Mitsushima, and K. Ota, Electrochim. Acta, to be submitted.
3. 3) Fuel Cell Commercialization Conference of Japan (FCCJ), Proposals of the development targets, research and development challenges and evaluation methods concerning PEFCs, http://www.fccj.jp/pdf/23_01_kt.pdf.