00290nam a2200121Ia 45000030006000000080041000060400015000471000022000622450046000842600009001305460012001390050017001510STCL150530s9999    xx            000 0 und d  aSTCLcSTCL  aSommerfeld Arnold  aPartial differential equations in physics  c1964  aEnglish20220125165943.0