1. Szecsenyi J, Uphoff H, Ley S, Brede HD. Influenza surveillance: experiences from establishing a sentinel surveillance system in Germany. J Epidemiol Community Health. 1995;49(Suppl 1):9–13.
2. ECDC European Influenza Surveillance Network . http://ecdc.europa.eu/en/healthtopics/influenza/EISN/Pages/index.aspx . Accessed 8 August 2016.
3. WHO Global Influenza Programm. http://www.who.int/influenza/en/ . Accessed 8 August 2016.
4. Martirosyan L, Paget WJ, Jorgensen P, Brown CS, Meerhoff TJ, Pereyaslov D, et al. The community impact of the 2009 influenza pandemic in the WHO European region: a comparison with historical seasonal data from 28 countries. BMC Infect Dis. 2012;12:36.
5. Buda S, Köpke K, Prahm K, Schweiger B, Wedde M, Duwe S, Buchholz U, Heiden Mad, Haas W Bericht zur Epidemiologie der Influenza in Deutschland Saison.2014. /15; https://influenza.rki.de/Saisonbericht.aspx . Accessed 8 August 2016.