HALSALL FRED. (2004). DATA COMMUNICATIONS COMPUTER NETWORKS AND OPEN SYSTEMS (4TH.). PEARSON EDUCATION.
Chicago-viite (17. p.)HALSALL FRED. DATA COMMUNICATIONS COMPUTER NETWORKS AND OPEN SYSTEMS. 4TH. NEW DELHI: PEARSON EDUCATION, 2004.
MLA-viite (9. p.)HALSALL FRED. DATA COMMUNICATIONS COMPUTER NETWORKS AND OPEN SYSTEMS. 4TH. PEARSON EDUCATION, 2004.
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