Sousa, M. da C.S. de, Araújo, P.L. da C.P. e Tannuri-Pianto, M.E. (2012) “Residual and technical tax efficiency scores for Brazilian municipalities: a two-stage approach”, Estudos Econômicos (São Paulo), 42(1), p. 43–74. doi:10.1590/S0101-41612012000100002.