Held , Gilbert. <br/><br/>
Understanding data communications  

 - 6th edition. 
 - Delhi :  Techmedai,  1994 
 - 619. 
<br/><br/><label>ISBN: </label>8176353191  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Applied physics
<br/><br/><label>Dewey Class. No.: </label>621.382  / HEL