00464    a2200145   450000500170000002000180001708200220003510000240005724500600008125000190014126400800016030000440024052600120028470000220029620260420145027.0  a0-321-04538-6  a515.35 D4382 19971 aDerrick, William R.  aElementary differential equations /cWilliam R. Derrick  aFourth Edition 1aUnited States of AmericabAddison-Wesley Educational Publishers Inc.;c1997  a404 pages, An 23bIllustrations;c26 cm  a500-5991 aGroosman, Stanley