1. K. Kordesch, G. Simader , Fuel Cells and Their Applications, VCH, New York, 1996 (Chapter 4).
2. S.G. Ehrenberg, T. Serpico, G.E. Wnek, J.N. Rider, U.S. Patent 5,468,574 (1995).
3. J. Wei, C. Stone, A. Steck, U.S. Patent 5,422,411 (1995).
4. C. Andreola, F.P. Chlanda, J.P. Huang, U.S. Patent 5,643,968 (1997).