2002; 180(1-2):29-48. | fulltext (doi)00108-6) | MR 1950747 | Zbl 1015.92036
[18] VAN DEN DRIESSCHEP, WATMOUGHJ. Reproduction numbers and sub-threshold endemic equilibria for compartmental models of disease transmission. Mathematical Biosciences. 2002; 180(1-2):29-48. | fulltext (doi)00108-6) | MR 1950747 | Zbl 1015.92036