00271nam a2200121Ia 45000030006000000080041000060400015000471000013000622450036000752600009001115460012001200050017001320STCL150530s9999    xx            000 0 und d  aSTCLcSTCL  aHeap Ken  aGroup theory for Social workers  c1977  aEnglish20220125165729.0