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Winkelmann J, Muench U, Maier CB.Winkelmann J, et al. Among authors: maier cb.BMC Health Serv Res. 2020 Oct 12;20(1):937. doi: 10.1186/s12913-020-05760-y.BMC Health Serv Res. 2020.PMID: 33046077Free PMC article.