title: How to retrieve book's information in XML/JSON from library of congress by ISBN
body: <p>The Library of Congress has a site to search books by ISBN.  A simple way to retrive book's information is using a URL like:</p>
  
  <pre><code>http://lccn.loc.gov/2009019559/mods
  </code></pre>
  
  <p>where it returns a XML structure that may parse easily.  The URL requires a unique LCCN number in the the following format:</p>
  
  <pre><code>http://lccn.loc.gov/[lccn]/mods
  </code></pre>
  
  <p>I have a batch of books that has ISBN encoded in barcode.  How may I retrieve/convert ISBN to LCCN in order to retrieve the XML data of the book?</p>