What is a good indicator?
If a language often pops up on google, it usually just means that many people have problems with it. Not that it is that popular.
The most programming-related questions here on SO are C#-related, this just says the same.
Also: popularity varies dramatically in different areas of development. For example: for embedded programs, C is still king. But in casual Web Development, Dynamic languages rule. For the Gaming industry C++ rocks. And so on. (of course i have no "official" papers to confirm this statements ;) )
Unfortunately, all the "ranking"-pages i've seen so far don't respect the different programming areas, and most of them rely on some google search data. Don't believe anything written there as a fact.
If you just need a page that approves any of your statements in your paper, you'll find sources for everything.