Journal of Mathematical Analysis and Applications.2004; 298(2):418-31. | fulltext (doi) | MR 2086967 | Zbl 1063.92037
[23] BRAUERF. Backward bifurcations in simple vaccination models. Journal of Mathematical Analysis and Applications.2004; 298(2):418-31. | fulltext (doi) | MR 2086967 | Zbl 1063.92037