00337nam a2200109Ia 4500008004100000040003800041100001700079245005600096260004800152300001100200653001600211211215s9999    xx            000 0 und d  cJayakar Knowledge Resource Centre  aPerrine, J O 0aPhysics and mathematics in electrical communication  bJohn F Rider Publishers IncaNew Yorkc1958  a265 p.  aEngineering