Ramadan PA, Araújo FB de, Ferreira Junior M. A 12-month follow-up of an influenza vaccination campaign based on voluntary adherence: report on upper-respiratory symptoms among volunteers and non-volunteers. Sao Paulo Med J [Internet]. 2001 Jul. 7 [cited 2025 Oct. 16];119(4):142-5. Available from: https://periodicosapm.emnuvens.com.br/spmj/article/view/2770