S. M. L. Lima, M. C. Portela, M. A. D. Ugá, P. R. Barbosa, S. Gerschman, and M. M. Vasconcellos, “ Philanthropic hospitals and the operation of provider-owned health plans in Brazil ”, Rev. saúde pública, vol. 41, no. 1, pp. 116–123, Feb. 2007, doi: 10.1590/S0034-89102007000100016.