@article{articleac5013ed,
title   = {Effects of vaccination programmes on transmission rates of infections and related threshold conditions for control},
author = {Coutinho, Francisco Antônio Bezerra and Massad, Eduardo and Burattini, Marcelo Nascimento and Yang, H M and Azevedo Neto, Raymundo Soares de},
year = {1993},
doi = {10.1093/imammb/10.3.187},
journal   = {Ima Journal of Mathematics Applied in Medicine and Biology}
}