1. R. C. Bray, P. F. Knowles, and L. S. Meriwether,“ESR and the Role of Molybdenum in Enzymic Catalysis by Milk Xanthine Oxidase,” in: “Magnetic Resonance in Biological Systems,” A. Ehrenberg, B. G. Malmstrom, and T. Vanngard, eds., Pergamon Press, Oxford (1967), p. 249.
2. H. Beinert and W. H. Orme-Johnson, “Electron Spin Relaxation as a Probe for Active Centers of Paramagnetic Enzyme Species,” in ref. 1, p. 221.
3. A. Nason, “Nitrate Reductases,” in: “The Enzymes,”P. D. Boyer, H. Lardy, and K. Myrback, eds., Vol. 7, Academic Press, New York, N.Y. (1963), p. 587.
4. R. C. Bray and J. C. Swann, “Molybdenum-Containing Enzymes,” Struct. and Bonding, 11:107 (1972).
5. K. B. Taylor, “Enzymology of Nitrogent Fixation in Cell-free Extracts of Clostridium Pasteurianum”` J. Biol. Chem., 244:171 (1969).