Isolation and Characterization of Cellulolytic Nitrogen Fixing Azotobacter species from Wheat Rhizosphere of Khyber Pakhtunkhwa B Ahmad, S Nigar, NA Malik, S Bashir, J Ali, S Yousaf, JA Bangash, I Jan World Applied Sciences Journal 27 (1), 51-60, 2013 | 25 | 2013 |