1. Solubilization of rock phosphate by microorganism isolated from Bihar soil;Ahmad;J. Can. Appl. Microbial.,1968
2. Introduction to Soil Microbiology;Alexander,1977
3. Effectiveness of barley inoculation with root diazotrophic bacteria and their survival depending on soil–temperature and moisture;Belimov;Microbiol,1994
4. The Nature and Properties of Soils;Brady,1990
5. Standard Methods for the Examination of Water and Wastewater;Clesscerl,1998