Heckler, João Carlos, and Paulo Regis Ferreira da Silva. “Crop Sequence and Rotation Systems With Summer Crops in a Growing Season”. Pesquisa Agropecuaria Brasileira, vol. 20, no. 9, Apr. 2014, pp. 1069-76, doi:10.1590/S1678-3921.pab1985.v20.16215.