M. A. Gouvêa, M. C. Farina, and P. S. Varela, “The Differentiation of the Groups 4 e 5 of Municipalities in the state of São Paulo according to IPRS and Based on the Constitutional Transferences and Income Tributary Taxes - an Application of the Discriminant Analysis”, Rev. Bras. Gest. Neg., vol. 9, no. 24, pp. 01–14, Aug. 2007.