Marques, Marcelo Volpatto, et al. “Sulfonamides Quantification in Milk by High Performace Liquid Chromatography via Azoderivatives”. Pesquisa Agropecuaria Brasileira, vol. 43, no. 12, Jan. 2009, pp. 1817-20, doi:10.1590/S1678-3921.pab2008.v43.1214.