Sulkin, Allan. <br/><br/>
PBX systems for IP telephony  
Allan Sulkin. 
 - New York :  McGraw-Hill,  2002. 
 - viii, 487 p. :  ill. ;  24 cm. 
 - McGraw-Hill telecom professional .
<br/><br/> Includes index. 
<br/><br/><label>ISBN: </label>0071375686 
<br/><br/><label>LCCN: </label>2002512119 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Internet telephony.--EL<br/>Telephone--Private branch exchanges.
<br/><br/><label>Dewey Class. No.: </label>621.385 SUL