000 00281nam a22001217a 4500
020 _a3-211-81784-0
082 _a621.382 SEC'L
100 _aLONGS, G
_974224
245 _aSECURE DIGITAL COMMUNICATION
260 _aNEWYORK
_bSPRINGER VERLAG
_c1983
300 _a332P
942 _cBK
999 _c579787
_d579787