00289nam a2200109Ia 4500008004100000041000800041100001900049245004900068250001100117260004300128365000800171231011s9999    xx            000 0 und d  aeng  aWilliam A.Shay  aUnderstanding Data Communications & Networks  a2001 2  bVikas Pubs. House Pvt ltd ,New Delhi -  b350