The first comment has it spot-on for the first example: the html version is an alternate version -- it's not the same content. The example of content distribution networks (and other mirrors) is much better.
The syntax is very strange.<p>rel-canonical: <a href="http://www.example.com/white-paper.html" rel="nofollow">http://www.example.com/white-paper.html</a><p>would have been a better one.