Understanding the Nature of Metadata – A Systematic Review - Ulrich, Hannes; Kock-Schoppenhauer, Ann-Kristin; Deppenwiese, Noemi; Gött, Robert; Kern, Jori; Lablans, Martin; Majeed, Raphael W.; Stöhr, Mark; Stausberg, Jürgen; Varghese, Julian; Dugas, Martin; Ingenerf, Josef (Journal of Medical Internet Research, 2022)