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://journals.vu.lt./nonlinear-analysis/article/view/14113. Acesso em: 27 apr. 2025.