Moraes, A.P.P., Barreto, S.M., Passos, V.M.A., Golino, P.S., Costa, J.A. and Vasconcelos, M.X. 2011. Incidence and main causes of severe maternal morbidity in São Luís, Maranhão, Brazil: a longitudinal study. São Paulo Medical Journal. 129, 3 (May 2011), 146–152.