1. W.J. Lywood, J. Lloyd, D.E. Ridler, M.V. Twigg, in: M.V. Twigg (Ed.), Catalysis Handbook, 2nd ed., Wolfe Publishing, London, 1989
2. S. Strelzoff, Technology and Manufacture of Ammonia, Wiley, New York, 1981, p. 1
3. Cobalt/manganese oxide water gas shift catalysts