TY  - BOOK
AU  -  Fitzgerald, Jerry. 
TI  -  Business data communications : basic concepts,security, and design,3rd ed. / Jerry fitzgerald. 
SN  - 0471517836
U1  - 004.6 FIR 
CY  -   New York : Wiley, c1990. 
KW  -  Data transmission systems.
ER  -