000 00235nam a2200097 4500
245 _aDifferential equations
_cL.W.F. Elen
100 _aElen, L. W. F.
260 _aLondon
_bMacmillan
_c1965
300 _apts. ; 22cm.
082 _a515.35
_bELE
999 _c24536
_d24536