000 00312nam a2200121Ia 4500
008 250409s9999 xx 000 0 und d
020 _a81-317-0872-1
082 _a4.6
_bHEL
100 _aHeld, Gilbert
245 0 _aUnderstanding data communications 7/E
260 _aVidhyanagar
_bpearson
_c2006
365 _a599
999 _c254455
_d254455