N. C. ONWUBIKO, M. I. UGURU, and G. O. CHIMDI, “Pattern of variation and grouping of qualitative morphological characters of bambara groundnut (Vigna subterranea (L.) Verdc.)”, aas, vol. 115, no. 2, pp. 437–447, Jun. 2020, doi: 10.14720/aas.2020.115.2.1283.