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HTML is good for debugging, but probably is not suitable for your application.
See complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <allpages>
      <p pageid="57" ns="0" title="Background" />
      <p pageid="183" ns="0" title="BlockCharStates" />
      <p pageid="184" ns="0" title="BranchCharStates" />
      <p pageid="163" ns="0" title="Catalogue of Life" />
      <p pageid="407" ns="0" title="Catalogue of Life policy" />
      <p pageid="387" ns="0" title="Change items displayed" />
      <p pageid="180" ns="0" title="CharStateDetails" />
      <p pageid="178" ns="0" title="CharTypes" />
      <p pageid="330" ns="0" title="Citation" />
      <p pageid="235" ns="0" title="CiteInfoFlags" />
    </allpages>
  </query>
  <query-continue>
    <allpages apfrom="Cites" />
  </query-continue>
</api>