Document your research as you go along. Keep notes about your process and sources. If you refer to a source while you're writing, quickly jot down the source or author name, title, and page number, so you can remember where it came from -- it's okay to re-format the citation later on.
Use a variety of sources, such as combination of books, articles, and primary resources.
Don't expect to find the 'perfect source'. Your topic is complex and you will need to weave together several threads of research in a new way.
Be flexible with search terms. If one word doesn't work, can you re-phrase it another way? For example, are there alternative spellings, past vs. present place names, etc.
The attached brainstorming worksheet may give you some ideas.
If you would like in-depth help with research, make an appointment with your librarian by completing the online form at the link below: