Dang, Luan; Jennings, Cullen & Kelly, David <br/><br/>
Practical voip using vocal 

 - Shroff Publishers & Distributors Pvt. Ltd., Mumbai  2002 
 - xvii,502,7 
<br/><br/><label>ISBN: </label>81-7366-439-0 
<br/><br/><label>Dewey Class. No.: </label>621.38212 Dan