Modern communications/ 
Thomas H. Crowley...[etal.] 
 - New York:  Columbia University Press,  c1962 
 - xi, 340 p.;  23 cm. 
<br/><br/> Includes index 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Telecommunication systems<br/>Telephone systems<br/>Computer networks
<br/><br/><label>Dewey Class. No.: </label>621.38