Caballero, Segundo S. Urquiaga, et al. “Leaching of N Derived from the Soil and from [(15NH4) 2SO4] Fertilizer During the Growth Cycle of Bean Plants”. Pesquisa Agropecuaria Brasileira, vol. 21, no. 1, Apr. 2014, pp. 25-31, doi:10.1590/S1678-3921.pab1986.v21.14652.