Some webmasters are obsessed with checking backlinks at Google. The only way to do this in the past was to use the link operator, doing a search on Google for link:www.domain.com. Using this method would only show a small percentage of links that Google knew about.
Additionally you can download the information for further study.
One thing to keep in mind. Even though Google is showing a link, does not mean they are placing any value on the link.