TY  - BOOK
AU  -  Shelly,gary b / cashman, thomas j /pratt,philip j 
TI  -  Business data communications : introductory concepts and techniques 
SN  - 0133484831
U1  - 004.6 SHE 
CY  -  Prentice hall 
KW  -  Data trasmission systems  2.  Computer networks
ER  -