00373nam a2200121Ia 4500008004100000082001500041100002300056245004100079260003600120300001000156600001700166650006800183140224s9999    xx            000 0 und d  a621.385 M2  aJain, Gyan C., ed.  aPractical value equivalents and data  aDelhibBusiness Promotionc1977  a176p.  aC. Gyan Jain  aElectron tubes,Electric valves,Electronic circuits,Vacuum-tubes