Use encyclopedia references to build background knowledge. Do not direct quotes from these resources. Instead use them to build background information to improve your deep research.
Use research databases for information and for citations. You can separate your search into primary sources, journals, newspapers, articles.
Primary source documents are the most credible resources available for historical papers. Use these resources for quotations to strength the argument in your paper.
These contain both primary and secondary resources.
Check out the EHS LibGuide Citation page