<?xml version='1.0'?>

<reference anchor='RFC3581'>

<front>
<title>An Extension to the Session Initiation Protocol (SIP) for Symmetric Response Routing</title>
<author initials='J.' surname='Rosenberg' fullname='J. Rosenberg'>
<organization /></author>
<author initials='H.' surname='Schulzrinne' fullname='H. Schulzrinne'>
<organization /></author>
<date month='August' year='2003' /></front>

<seriesInfo name='RFC' value='3581' />
<format type='TXT' octets='66133' target='ftp://ftp.isi.edu/in-notes/rfc3581.txt' />
</reference>
