Dortzbach, Denilson, et al. “Inceptisol Surface Diagnostic Horizons and Use of δ13C As an Additional Attribute in the Soil Classification”. Pesquisa Agropecuaria Brasileira, vol. 51, no. 9, Oct. 2016, pp. 1339-48, doi:10.1590/S1678-3921.pab2016.v51.22224.