Ampomah, OY, E Ofori-Ayeh, B Solheim, and MM Svenning. “Host Range, Symbiotic Effectiveness and Nodulation Competitiveness of Some Indigenous Cowpea Bradyrhizobia Isolates from the Transitional Savanna Zone of Ghana”. African Journal of Biotechnology 7, no. 8 (August 30, 2010). Accessed October 3, 2026. https://www.ajol.info/index.php/ajb/article/view/58589.