000 00314nam a2200157Ia 4500
020 _aNULL
082 _aNULL
100 _aHalsall, Fred
245 0 _aData Communications, Computer Networks and Open Systems
250 _a-
260 _a-
_b-
300 _aNULL
500 _a0
650 _a-
942 _cBK
999 _c34883
_d34883