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Fortis A, García-Macedo R, Maldonado-Bernal C, Alarcón-Aguilar F, Cruz M.Fortis A, et al. Among authors: cruz m.Salud Publica Mex. 2012 Mar-Apr;54(2):171-7. doi: 10.1590/s0036-36342012000200014.Salud Publica Mex. 2012.PMID: 22535177Review.Spanish.