00292nam a2200121Ia 45000030006000000080041000060400015000471000020000622450036000822600023001185460012001410050017001530STCL150530s9999    xx            000 0 und d  aSTCLcSTCL  aPetrovsky, I.G.  aPartial dDifferential equations  bIntersciencec1964  aEnglish20220125165942.0