title: Looking back or looking forward?
authors.forename: A
authors.initials: A
authors.lastname: Sommer
authors.forename: W C
authors.initials: WC
authors.lastname: Steinmann
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods* / Q000592:standards; D003625:Data Collection / Q000379:methods*; D006801:Humans; D011446:Prospective Studies; D012189:Retrospective Studies