Influenza C virus in pre-school children with respiratory infections: retrospective analysis of data from the national influenza surveillance system in Germany, 2012 to 2014 Fritsch, Annemarie and Schweiger, Brunhilde and Biere, Barbara, Eurosurveillance, 24, 1800174 (2019), https://doi.org/10.2807/1560-7917.ES.2019.24.10.1800174