php - Wordpress getting author's Google+ profile url
At the author page in wordpress I would like to add the Google+ profile link of a author.
I know how to add things like site_url, twitter, facebook by the_author_meta('string') but I don't know the name to show a google+ profile link. I tried 'google' but no luck.
In the documentation of wordpress I can't find anything about Goole+ profile links.
Thanks in advance,