Thematic Afternoon: German-speaking Traditions in Mathematics Education Research Panel - Hans-Niels Jahnke, Marcus Nührenbörger, Bettina Rösken-Winter, Angelika Bikner-Ahsbahs, Andreas Vohns, Lisa Hefendehl-Hebeker, Rudolf vom Hofe, Rolf Biehler, Uwe Gellert, Götz Krum - University of Hamburg