title: [Düker's new version of mathematical problem-solving].
authors.forename: O
authors.initials: O
authors.lastname: Heller
mesh_terms: D005860:Germany, West; D049673:History, 20th Century; D006801:Humans; D008433:Mathematics; D011340:Problem Solving; D011589:Psychology, Experimental / Q000266:history
vernacular_title: Eine neue Version des Rechnens nach Düker.