1. J. P. Thompson and V. B. D.Skerman , Azotobacteraceae: the Taxonomy and Ecology of the Aerobic Nitrogen-Fixing Bacteria , Academic Press , London, UK , 1979
2. Azotobacter Genomes: The Genome of Azotobacter chroococcum NCIMB 8003 (ATCC 4412)
3. J. H. Becking , in The Prokaryotes , ed. M. Dworkin , S. Falkow , E. Rosenberg , K. H. Schleifer and E. Stackebrandt , Springer , New York, NY, USA , 3rd edn, 2006 , vol. 6, pp. 759–783
4. S. A. Wani , S.Chand , M. A.Wani , M.Ramzan and K. R.Hakeem , in Soil Science: Agricultural and Environmental Prospectives , ed. K. R. Hakeem , J. Akhtar and M. Sabir , Springer International Publishing , Cham , 2016 , pp. 333–348 , 10.1007/978-3-319-34451-5_15
5. K. V. B. R. Tilak , K. K.Pal and R.Dey , Microbes for Sustainable Agriculture , I.K. International Publishing House , New Delhi, India , 2010