CWI
Department of Analysis, Algebra and Geometry [AM]

Diekmann, O., Heesterbeek, H.& Metz, J. A. J. (1989). On the definition and the computation of the basic reproduction ratio : $R_ 0$ in models for infectious diseases in heterogeneous populations. In Department of Analysis, Algebra and Geometry [AM] (R 8912.). CWI.