How do I find references for my thesis?

Hi all. Please advise me for finding the relevant information and correct references for my thesis? I have done research and consulted a wide literature back then. I noted some of the references, but now when I began writing my thesis, I felt as if those references are way too limited. I should add some more for explaining things better but now how can I? (just for FYI my research is all about American Feminism in 20th century)

Posted in: Methodology