00343nam a22001457a 4500003001200000005001700012008004100029020000600070040001200076082001500088100001700103245003500120260001100155650003100166NUST - PNEC20170116180930.0150905b        xxu||||| |||| 00| 0 eng d  a-  cLIBRARY  a621.31 VAS  aVas, Gratian  aSources of energycGratian Vas  cc.1998  bElectrical EngineeringxEL