000 003060000a22001330004500
245 _aModern communication systems
100 _aCoates, R.F.W.
260 _aLondon
_bMacmillan
_c1975
300 _aviii, 292p. : ill.
020 _a0333150244
080 _a621.39
_bC6
041 _aEN
942 _cBK
999 _c111250
_d111250