The effect of the incidence function on the existence of backward bifurcation. Letters in Biomathematics, [S. l.], v. 3, n. 1, p. 181–199, 2023. DOI: 10.30707/LiB3.1Gerberry. Disponível em: https://lettersinbiomath.org/manuscript/index.php/lib/article/view/42.. Acesso em: 5 jul. 2024.