000 00286nam a2200121Ia 4500
008 220201s1947 xx 000 0 eng d
082 _a621.3192
_bSIG
100 _aSignals
245 0 _aHandbook of line Comunication
260 _alondon
_bH.M.S.O
_c1947
300 _a905
942 _2ddc
999 _c13720
_d13720