Morgado, Luiz Balbino, and Robert Williams Willey. 2003. “Effects of Plant Population and Nitrogen Fertilizer on Yield and Efficiency of Maize-Bean Intercropping”. Pesquisa Agropecuaria Brasileira 38 (11):1257-64. https://doi.org/10.1590/S1678-3921.pab2003.v38.6698.