000			00321nam a2200133Ia 4500
008			170527s2016||||xx |||||||||||||| ||und||
020			_a81-203-1080-2
082			_a004.6 _bH366u4
100			_aGilbert Held
245		0	_aUnderstanding data communications
250			_a4th
260			_bPrentice-Hall _c2004 _aNULL
300			_a0 p.
942			_cBK
999			_c2720 _d2720