Silva, E. C. da, Ribeiro, V. Q. and Andrade, D. F. de (2014) “The use of a quadratic model to determine the size and shape of plots in experiments with cowpea intercropped with corn”, Pesquisa Agropecuaria Brasileira, 19(10), pp. 1267–1270. doi: 10.1590/S1678-3921.pab1984.v19.16129.