@inproceedings{inproceedings3ecc3a86,
title   = {Quasi-cyclic phenomenon in epidemics: bifurcation condition},
author = {Yang, H M and Yamamoto, J F and Silveira, A S B and Azevedo Neto, Raymundo Soares de and Massad, Eduardo},
year = {1994},
publisher = {International Society of Infectious Diseases},
booktitle   = {International Congress for Infectious Diseases}
}