1 x motor boats and boat engines, ed. by the editors of the magazine Die Yacht, Yacht Library Vol. III, 2nd edition, Berlin 1910, 2 x driving course (formerly chauffeur course). Publicly understandable textbook together with questions and answers for the examination of motor vehicle owners and drivers, by Ad. König, 8th improved edition, Berlin 1925 and 25th improved edition, Braunschweig and Berlin 1950s, each with signs of age
