BUONOMO, B.; LACITIGNOLA, D. On the backward bifurcation of a vaccination model with nonlinear incidence. Nonlinear Analysis: Modelling and Control, [S. l.], v. 16, n. 1, p. 30–46, 2011. DOI: 10.15388/NA.16.1.14113. Disponível em: https://www.journals.vu.lt/nonlinear-analysis/article/view/14113.. Acesso em: 14 may. 2024.