Flach, L., L. Karam de Mattos, A. Renan Will, and L. Facciuto Roschel. “Efficiency of Expenditure on Education and Learning by Brazilian States: A Study With Data Envelopment Analysis”. Contabilidad Y Negocios, Vol. 12, no. 23, Nov. 2017, pp. 111-28, https://revistas.pucp.edu.pe/index.php/contabilidadyNegocios/article/view/19355.