URDANETA, M. M. ; PRATA, A. ; STRUCHINER, C. J. ; TOSTA, C. E. ; TAUIL, P. ; BOULOS, M. . Spf66 Vaccine Trial In Brazil: Conceptual Framework Study Design And Analytical Approach. Revista da Sociedade Brasileira de Medicina Tropical, v. 29, n.3, p. 259-269, 1996.