00280nam a2200121Ia 45000030006000000080041000060400015000471000023000622450035000852600009001205460012001290050017001410STCL150530s9999    xx            000 0 und d  aSTCLcSTCL  aPervin William, J.  aFoundation of general topology  c1964  aEnglish20220125165938.0