1. Eurostat. People in the EU – population projections. Available at: http://ec.europa.eu/eurostat/statistics-explained/index.php/People_in_the_EU_%E2%80%93_population_projections#Further_Eurostat_information. [Accessed on March 27, 2018].
2. European Commission. Population ageing in Europe. Facts, implications and policies. Available at: https://ec.europa.eu/research/social-sciences/pdf/policy_reviews/kina26426enc.pdf. [Accessed on March 27, 2018].
3. European Centre for Disease Prevention and Control. Seasonal Influenza. Factsheet for health professional. Available at: http://ecdc.europa.eu/en/healthtopics/seasonal_influenza/basic_facts/Pages/factsheet_professionals_seasonal_influenza.aspx. [Accessed on March 27, 2018].
4. Clinical and economic burden of community-acquired pneumonia among adults in Europe;Welte;Thorax,2012
5. Clinical practice: herpes zoster;Cohen;N Engl J Med,2013