00269nam a2200097Ia 4500008004100000082001500041100002700056245003700083260004300120300000800163190709s9999    xx            000 0 und d  a517.38F947  aThornton C. FRY, PH,D. 0aElementary Differential Equation  aLondonbD. van Nostrand Company,c1929  a255