000 00284nam a2200121Ia 4500
008 220201s1959 xx 000 0 eng d
082 _bSHA
100 _aSharad, R. L.
245 0 _aElectronic communication
260 _aNew york
_bMc graw Hill
_c1959
300 _a937
942 _2ddc
999 _c18244
_d18244