00309nam a2200121Ia 4500008004100000041000800041082001600049100001800065245004500083260003700128300001500165365000700180240624s9999    xx            000 0 und d  aeng  a621.382 GUP  aGUPTA NIRAJ K  aBUSINESS OF TELECOMMUNICATION NETWORKING  c2000aNew DelhibTata McGrawhill  axxi, : 506  cRS