Zürcher, K., M. Zwahlen, C. Berlin, M. Egger, and L. Fenner. “Trends in Influenza Vaccination Uptake in Switzerland: Swiss Health Survey 2007 and 2012”. Swiss Medical Weekly, vol. 149, no. 0304, Jan. 2019, p. w14705, doi:10.4414/smw.2019.14705.