Bezerra Neto, F. and Robichaux, R. H. (1996) “Spatial arrangement and density effects on an annual cotton/cowpea/maize intercrop. I. Agronomic efaciency”, Pesquisa Agropecuaria Brasileira, 31(10), pp. 729–741. doi: 10.1590/S1678-3921.pab1996.v31.4543.