00311nam a2200133Ia 45000030006000000080041000060400015000471000019000622450048000812500010001292600009001395460012001480050017001600STCL150530s9999    xx            000 0 und d  aSTCLcSTCL  aSommerfeld, A.  aPractical differential equations in physics  aFirst  c1964  aEnglish20220125170127.0