000 00311nam a2200121Ia 4500
008 220201s1970 xx 000 0 eng d
041 _aENG
100 _aBISWAS, NRIPENDRA N
245 0 _aPRINCIPLES OF TELEPHONY
260 _aLONDON
_bTHAMES AND HUDSON PUBLISHING COMPANY
_c1970
300 _a138
942 _2ddc
999 _c44533
_d44533