Research paper topic: Separation Of Church and State help?

I am doing a research paper on why religion should be completely separate from the state, and should hold no influence over the functions of a government. Topics included in this paper are taxing churches, Asia Bibi, radical Islam(other religions), proposition 8, religion influence on war, and separation of religious influence in government (ex: In God We Trust, One Nation Under God ect.). Can you please ist me with any books that I can use to pull information out of, I need a total of 7. Any books would help regarding churches, church money, churches and wars, and books regarding the listed topics. thanks in advance! Non-Fiction books please!