canonical URL

Just came across these URLs

http://www.google.com/search?hl=en&q=link%3Ahttp%3A%2F%2Fworldcatlibraries.org%2Foclc%2F65187392&btnG=Search

and

http://www.google.com/search?hl=en&q=link%3Ahttp%3A%2F%2Fworldcat.org%2Foclc%2F65187392&btnG=Search

I was trying to compare same Worldcat pages with different URLs, by google backward link search features (http://www.google.com/advanced_search)

So http://worldcat.org/oclc/65187392 and
http://worldcatlibraries.org/oclc/65187392
are same page, however due to variants of these URLs, Google treats them as different URLs, and this certainly doesn't help moving up these pages up in Google search results, if we consider the inbound link factor in PageRank.