1. Potential for nitrogen fixation in maize genotypes in Brazil;von Bülow,1975
2. The effect of corn root excretions on atmospheric nitrogen fixation by Azotobacter chroococcum grown in pure culture;Federov,1944
3. The acetylene-ethylene assay for N, fixation : laboratory and field evaluation;Hardy;Plant Physiology,1968
4. Chemical analysis of microbial cells;Herbert,1971
5. The effect of root excretions on the growth of Azotobacter and other soil microbes;Krasilnikov,1934