Books regarding atheism

[Belacqua]

Those that advocate for something else must provide something else than philosophical arguments. 

This shows that you have very strong beliefs, and that these beliefs are the foundation of your atheism. (Here I am using the word "belief" just to mean "something you hold to be true.") 

By denying the worth of philosophical arguments, I'm guessing (please correct me if I'm wrong) that you consider only scientific-type evidence as persuasive. This would be the standard among the type of atheists who post on web sites like this one. 

So your strong belief in certain epistemological or metaphysical conclusions -- that only empirical evidence is reliable, that what science tells us is the most reliable -- and that this commitment (which is unprovable in itself) is why you are an atheist. 

It may not be chronologically first -- maybe you were an atheist without justification first, and then committed to these principles -- but currently they form the philosophical foundation for your atheism.

I don't need to justify my atheism.

On a forum like this one no one will demand that you justify your philosophical positions, because they are more or less the default among this type of atheist. 

However, they are positions that can and should be justified. No one should pretend that he completely lacks philosophical foundations for his atheism when he so clearly has them, as you do. 

I am not saying they are BAD foundations, or that you are wrong to hold these positions. I am only saying that you do have philosophical commitments, that they underlie your atheism, and therefore your atheism is not a pure lack but the conclusion based on principles.