Donkova, R., Nedyalkova, K., Perfanova, J., & Valchovski, H. (2016). Response of Cowpea (Vigna unguiculata L.) to Inoculation with Nitrogen Fixing Bacteria. Bulgarian Journal of Soil Science, Agrochemistry and Ecology, 50(1), 21-25. https://agriacad.eu/ojs/index.php/bjssae/article/view/2035