It's the topic for my term paper, and I need help starting it.
Two things before I post.
1)Could you specify what you mean by beliefs?
2)While I'm very willing to point you in the right direction I'm not going to write your paper for you.
Igor de Rachewiltz is always a good scholar to start with when researching the Mongols. But I agree with /u/rakony, this sub isn't about writing your essays for you.