@article{Remschmidt2016, author = "Cornelius Remschmidt and Ole Wichmann and Thomas Harder", title = "{Additional file 1: of Frequency and impact of confounding by indication and healthy vaccinee bias in observational studies assessing influenza vaccine effectiveness: a systematic review}", year = "2016", month = "12", url = "https://springernature.figshare.com/articles/journal_contribution/Additional_file_1_of_Frequency_and_impact_of_confounding_by_indication_and_healthy_vaccinee_bias_in_observational_studies_assessing_influenza_vaccine_effectiveness_a_systematic_review/4361900", doi = "10.6084/m9.figshare.c.3610913_D2.v1" }