The Fake Citation Fallacy: Claiming that a source had said something without providing any reason for your opponent to believe you. Example: two catholics are having an argument about abortion, and one of them says "Yeah well the church says it's okay", without saying where or in what document the church has said that. No, the burden is not on your opponent to go digging through source material looking for it. If you're going to make an argument that depends on external sources, at least give your opponent an easy way to look it up.
This fallacy is even worse when it's taken to an extent I call the Vague Fake Citation Fallacy: doing this with an alleged source so vague that it's impossible for your opponent to prove you wrong. Example: pretty much every sentence starting with "science has proven..." or "it is known..."
The Authoritarian Fallacy: Acting like a simple citation is proof of anything no matter how bizarre or even self-evidently false it is. Example: the citation to Libet's studies on Wikipedia's article on free will that says it's been proven scientifically that our decisions are made by our brains about ten seconds before we become aware of them. This is a pretty flat-out denial of the existence of free will, which is how we KNOW the mind works due to a little thing called INTROSPECTION and if you can even take this citation seriously then you're an idiot.