1. Eady, R. R. (1991) Adv. Inorg. Chem. 36, 77–102.
2. Arnold, W., Rump, A., Klipp, W., Priefer, U. B. & Puhler, A. (1988) J. Mol Biol. 203, 715–738.
3. Dean, D. R. & Jacobson, M. R. (1992) in Biological nitrogen fixation (Stacey, G., Evans, B. J. & Burris, R. H., eds) pp. 763–834, Chapman & Hall, New York.
4. Elmerich, C. (1991) in Biology and biochemistry of nitrogen fixation (Dilworth, M. J. & Glenn, A. R., eds) pp. 103–141, Elsevier, Amsterdam, New York.
5. Bishop, P. E. & Joerger, R. D. (1990) Annu. Rev. Plant Physiol. Plant Mol. Biol. 41, 109–125.