Hersent, Olivier. <br/><br/>
IP telephony :  packet-based multimedia communications systems / 
Olivier Hersent, David Gurle & Jean-Pierre Petit. 
 - Harlow :  Addison-Wesley,  cop. 2000. 
 - XVIII, 456 s. :  il. ;  23 cm. 
<br/><br/><label>ISBN: </label>0201619105 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Telefonia internetowa.
<br/><br/><label>Universal Decimal Class. No.: </label>621.395