M. López-Cervantes, A. Venado, A. Moreno, R. L. Pacheco-Domínguez, and G. Ortega-Pierres, “On the Spread of the Novel Influenza A (H1N1) Virus in Mexico”, J Infect Dev Ctries, vol. 3, no. 05, pp. 327–330, Jun. 2009.