00274nam a2200121Ia 45000030006000000080041000060400015000471000022000622450017000842600022001015460012001230050017001350STCL150530s9999    xx            000 0 und d  aSTCLcSTCL  aSpangenberg, K.R.  aVacuum tubes  bMcgraw hillc1984  aEnglish20220125170206.0