Reporting quality of trial protocols improved for non-regulated interventions but not regulated interventions: a repeated cross-sectional study - Lohner, Szimonetta (Verfasser); Bischoff, Karin (Verfasser); Wollmann, Katharina (Verfasser); Rehner, Laura (Verfasser); Meerpohl, Jörg J. (Verfasser); Blümle, Anette (Verfasser); Briel, Matthias (Verfasser) (Universität, 2021)