JournalsemVol. 53, No. 3Volume 53, No. 3 (1998) Elemente der Mathematikpp. 89–106On Nonconvex Caustics of Convex BilliardsOliver Knillpp. 107–111Teaching the Independence of Xˉ and S2Wiebe R. Pestmanpp. 112–118Regular Hexagons Associated to Triangles with Equal CentroidsZvonko Čerinpp. 119–125Zur Kurvendiskussion der PotenzsummenpolynomeDietmar Treiberpp. 126–130Aufgabenpp. 131–132Bücher und Computersoftware