Azevedo, Demóstenes Marcos Pedrosa de, et al. “Effect of Corn and Cowpea Planting Date on Perennial Cotton Association”. Pesquisa Agropecuaria Brasileira, vol. 20, no. 7, Apr. 2014, pp. 821-9, doi:10.1590/S1678-3921.pab1985.v20.15817.