Nitrogen Fixation: From Molecules to Crop Productivity Proceedings of the 12th International Congress on Nitrogen Fixation, Foz do Iguaçu, Paraná, Brazil, September 12-17, 1999 - Pedrosa, Fabio O.; Hungria, Mariangela.; Yates, Geoffrey.; Newton, William E. (Current Plant Science and Biotechnology in Agriculture,, 2000)