00352cam a2200121ua 4500041001000000082002100010100002200031245008700053260005200140300001200192504000500204700002100209  aengh  a621.3845bHAR/PR  aHarbottle, H.R  .  aPrinciples of telecommunications engineering / cH.R.Harbottle.hTextual Documents  aLondon : bEnglish Universities Press , c1962.  a373 ; .  a1 aHamman, G.L.B  .