da Silva, Eulene Francisco, et al. “Labile and Recalcitrant Fractions of Soil Organic Matter under Integrated crop‑livestock System”. Pesquisa Agropecuaria Brasileira, vol. 46, no. 10, Jan. 2012, pp. 1321-3, doi:10.1590/S1678-3921.pab2011.v46.9068.