000 00278nam a2200097 4500
080 _a621.39
_bHIL.79
245 _aTelecommunications switching principles
100 _aHills, M.T
260 _aLondon
_bGeorge Allen & Unwin
_c1979
300 _axiii+327
440 _vTelecommunication systems design Vol. <2=two>
999 _c27406
_d27406