Silveira, Pedro Marques da, et al. “Nitrogen Fertilization of Common Bean Grown under No-Tillage System After Several Cover Crops”. Pesquisa Agropecuaria Brasileira, vol. 40, no. 4, Apr. 2005, pp. 377-81, doi:10.1590/S1678-3921.pab2005.v40.6967.