One article that i found on the web was how stuff works "do parallel universes really exist?". The author of this article really did his homework because he explains everything so simple and easy to understand that you know he is an expert on this topic. There are also no spelling or grammar problems so it has been published and looked over many times. There is nothing out of the ordinary in this article so it is also reliable.
I have found books in library's all over but couldn't seem to find them when i got there, so i have looked at some books o papers online one is written by the scientist i want to interview so i know that it is very reliable. The paper is kind of difficult to read but i know must of what he is saying.