1. Abate T, Alene AD, Bergvinson D, Shiferaw B, Silim S, ORR A, Asfaw S (2012) Tropical grain legumes in Africa and south Asia: knowledge and opportunities. International crops research Institute for the Semi-Arid Tropics (ICRISAT)
2. Ayisi KK, Nkgapele RJ, Dakora FD (2000) Nodule formation and function in six varieties of cowpea (Vigna unguiculata L. Walp) grown in a nitrogen-rich field soil in South Africa. Symbiosis 28:17–31
3. Bekere W, Kebede T, Dawud J (2013) Growth and nodulation response of soybean (Glycine max L.) to lime, Bradyrhizobium japonicum and nitrogen fertilizer in acid soil at Melko, south western Ethiopia. International Journal of Soil Science 8(1):25–31.
https://doi.org/10.3923/ijss.2013.25.31
4. Dakora F, Keya S (1997) Contribution of legume nitrogen fixation to sustainable agriculture in sub-Saharan Africa. Soil Biol Biochem 29(5):809–817.
https://doi.org/10.1016/S0038-0717(96)00225-8
5. Dilnesaw, Z. Abadi, S, and Getahun, A. 2013. Genetic variability and heritability of soybean (Glycine max (L.) Merrill) genotypes in Pawe district, Metekel zone, Benishangule Gumuz regional state, north-western Ethiopia. Wudpecker J Agric Res, 2(9): 240–245