Ramadan, P. A., Araújo, F. B. de, & Ferreira Junior, M. (2001). A 12-month follow-up of an influenza vaccination campaign based on voluntary adherence: report on upper-respiratory symptoms among volunteers and non-volunteers. São Paulo Medical Journal, 119(4), 142–145. Retrieved from https://periodicosapm.emnuvens.com.br/spmj/article/view/2770