Paul E. Bishop Betancourt, D. A., Loveless, T. M., Brown, J. W., & Bishop, P. E. (2008). Characterization of diazotrophs containing Mo-independent nitrogenases, isolated from diverse natural environments. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 74(11), 3471–3480. https://doi.org/10.1128/AEM.02694-07 Qurollo, B. A., Bishop, P. E., & Hassan, H. M. (2001). Characterization of the iron superoxide dismutase gene of Azotobacter vinelandii: sodB may be essential for viability. Canadian Journal of Microbiology, 47(1), 63–71. https://doi.org/10.1139/cjm-47-1-63 Loveless, T. M., & Bishop, P. E. (1999). Identification of genes unique to Mo-independent nitrogenase systems in diverse diazotrophs. CANADIAN JOURNAL OF MICROBIOLOGY, 45(4), 312–317. https://doi.org/10.1139/w99-007 Loveless, T. M., Saah, J. R., & Bishop, P. E. (1999). Isolation of nitrogen-fixing bacteria containing molybdenum-independent nitrogenases from natural environments. Applied and Environmental Microbiology, 65(9), 4223–4226. Premakumar, R., Pau, R. N., Mitchenall, L. A., Easo, M., & Bishop, P. E. (1998). Regulation of the transcriptional activators AnfA and VnfA by metals and ammonium in Azotobacter vinelandii. FEMS Microbiology Letters, 164(1), 63–68. https://doi.org/10.1111/j.1574-6968.1998.tb13068.x Bishop, P. E., Jarlenski, D. M. L., & Hetherington, D. R. (1982). Expression of an alternative nitrogen fixation system in Azotobacter vinelandii. Journal of Bacteriology, 150(3), 1244.