Donkova, Radka, Kostadinka Nedyalkova, Jonita Perfanova, and Hristo Valchovski. “Response of Cowpea (Vigna Unguiculata L.) to Inoculation With Nitrogen Fixing Bacteria”. Bulgarian Journal of Soil Science, Agrochemistry and Ecology 50, no. 1 (March 30, 2016): 21–25. Accessed October 6, 2026. https://agriacad.eu/ojs/index.php/bjssae/article/view/2035.