title: Why does my RSS feed duplicate some entries?
body: <p>When reading my RSS feed with the Thunderbird feed reader, some entries are duplicated. <a href="https://en.wikipedia.org/wiki/Google_Reader" rel="nofollow noreferrer">Google Reader</a> does not have the same problem.</p>
  <p>Here is the faulty feed:
  <a href="http://plcoder.net/rss.php?rss=Blog" rel="nofollow noreferrer">http://plcoder.net/rss.php?rss=Blog</a></p>
  <p>There is a problem, but where?</p>
  <p>I added a <a href="https://en.wikipedia.org/wiki/Globally_unique_identifier" rel="nofollow noreferrer">GUID</a>, but the problem remains. Other feeds do not duplicate like mine, so I will do rework on this module and replace this old good code.</p>
  <p>Conclusion: I completely reworked the RSS generator code, and it's OK. I think I was using a very old version of <a href="https://en.wikipedia.org/wiki/Resource_Description_Framework" rel="nofollow noreferrer">RDF</a>.</p>