00265nam a2200121Ia 4500082002000000100001900020245004100039250000800080260002800088300001700116500000500133700000500138  a515.35bF735.DE  aForsyth, A. R.  aTreatise on differential equationsb  a6th  aLondonbMacmillanc1961  axviii, 583p.  a  a