Rocha, Gabriel Cipriano, et al. “Evaluation of Acid Digestion Techniques to Estimate Chromium Contents in Cattle Feces”. Pesquisa Agropecuaria Brasileira, vol. 50, no. 1, Jan. 2015, pp. 92-95, doi:10.1590/S1678-3921.pab2015.v50.19625.