000 00329nam a2200121Ia 4500
008 250409s9999 xx 000 0 und d
020 _a81-297-0211-8
082 _a4.6
_bHEL
100 _aHeld,Gilbert
245 0 _aUnderstanding data communications 7/E
260 _aVidhyanagar
_bPearson Education Asia
_c2003
365 _a295
999 _c251141
_d251141