Remember, an old-school rule of thumb is that academic papers should have approximately 1.5 citations per page. That would be a minimum of 18-20 sources and a max of 36 - 40. However, your paper may merit a close examination of a few major tomes, and you may have 5-10 sources, cited repeatedly.
What types of sources should you use?
Scholarly journal articles, reputable news sources, data to justify your argument