1. G. C. Sweeney, Proc. First Intl. Symposium Nitrogen Fixation, 648–655, Washington University Press (1976).
2. E. A. Harre and J. R. Douglas, Proc. First Intl. Symposium Nitrogen Fixation, 674–692. Washington University Press (1976).
3. Anon., Chem Eng News, 27–28 (1977).
4. Prospects for new nitrogen fixation processes