Mahler, Paul. <br/><br/>
Voip telephony with asterisk: a technical overview of the open source PBX   a technical overview of the open source PBX  
Paul Mahler. 
 - San Francisco, CA :  Signate,  2005. 
 - 291 p. :  ill. ;  24 cm. 
<br/><br/><label>ISBN: </label>0975999206