C. K. Takiguti, M. E. Sakuma, S. P. Curti, and G. R. Pacheco, “ An approach to the study of contagious disease epidemics: conceptual model based on spatial and functional scales of epidemic progression ”, Rev. saúde pública, vol. 20, no. 3, pp. 235–241, Jun. 1986, doi: 10.1590/S0034-89101986000300007.