Wikipedia itself isn't really a source anyway, it's a collection of sources. Most college level classes will not allow Wikipedia to be used as a source anyway.
If you trust a page on the internet to actually provide the correct source, you can use that as the source in your report, but you risk it being incorrect if checked. On top of that, if you are needing to write a correct works cited page, you'll need the writer, artist, date and correct indica of the comic.
Depends on the strictness of your teacher. If you are allowed to use Wikipedia, simply cite Wikipedia as your source. There are also plenty of other websites you can use. If you know what is posted is true, then there shouldn't be a problem. Check multiple sites. Shouldn't be that hard, Robin is a pretty popular character.
Also, you can use your own comic books.
Personal knowledge is allowed in writing/speech, but you need to add as many sources to the material as you can. Common knowledge is common knowledge, but other than that, you should try to cite something.
@King_Bradley: I've mentioned that before. Never get much replies from it though. I've actually pointed out that Other World has the same gravity as Earth, since when they go to the check out they are unaffected by any gravity. Same with Snake Way. Only on King Kai's planet was the gravity higher.