Search for secondary sources on your topic to see which primary sources they use and cite in their research.
These tertiary reference sources summarize research findings and resources. You may find citations for significant primary or secondary sources in encyclopedia articles or bibliographies around your research topic. Source books may include translated primary sources that you can use directly, or may have a citation for a full source you can find.
There are many other tertiary sources in the catalog that could be helpful. For example, this search may have some other useful source books.