Esparza, D. J., Nitsche, A., & Damaso, C. R. (2020). Investigations on the historical origin and evolution of the smallpox vaccine. Gaceta Médica De Caracas, 128(1S), S88-S97. Recuperado a partir de http://caelum.ucv.ve/ojs/index.php/rev_gmc/article/view/20443