Discuss TrackbackEntryExample here.
[ZhangYining RefactorOk] Again, this example is verbose, but from dicussions so far, it's one possibility.
<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://purl.org/echo/" version="1.0" xml:lang="en-us">
<title>Simple Echo Feed</title>
<entry>
<title>Original entry</title>
<content mode="xml">Yea!</content>
<id>http://purl.og/e45</id>
</entry>
<entry>
<id>http://foobar.org/12345</id>
<related>
<relationRole>http://purl.org/echo/trackback</relationRole>
<relationHref>http://purl.org/e45</relationHref>
<relationAuthor>
<name>Foo Bar</name>
<homepage>http://foobar.org/</homepage>
<weblog>http://foobar.org/weblog/</weblog>
<email>foo@bar.org</email>
<relationAuthor>
</related>
<title>TrackBack Example</title>
<content mode="xml">Ping!</content>
</entry>
</feed>
