good paper or essay or even book refuting christianity?

[Arp220]

The God Delusion by Dawkins is a pretty good read

[IronUnkind]

You'll have to forgive the lame responses. Atheists are used to taking orders from Captain Renault

[benjdm]

Atheism: The Case Against God by George H. Smith

[nescience]

Is there any particular aspect of Christianity you're trying to refute?

In the 2000 or so year history of the religion, there have been so many disagreements in interpretation that just about the only common claim you can attack is that Jesus is God's son (even the divinity vs. humanity of Jesus Christ is argued amongst Christians).

Since this very basic claim, much like any claim about the existence of God, typically distills into an irrelevant question of belief, any attempt to disprove it seems to be as fallacious as attempts to prove it. There are, however, many arguments that fairly convincingly poke holes in so-called "proofs" of the existence of God. This arguments form the basis of the atheistic viewpoint, which is more concerned with the idea that it is impossible to prove the existence of God than the idea that it is possible to prove the non-existence of God. If you want some historical viewpoints, I would look into the philosophical writings of St. Anselm (and to a lesser extent, Thomas Aquinas), who both attempted to prove the existence of God, and the various criticisms of their arguments (such as from Hume).

I don't know if this helps, but might give you something to consider as you read.