Subject encyclopedias are excellent starting points. Entries in them are written by scholars and provide not only overviews of topics, but usually also a discussion of the historiography of the topic. The bibliographies found at the end of entries are particularly valuable for identifying scholarly editions of primary sources as well as secondary sources.
Start with the subject encyclopedias listed below. You also may want to consult some of the subject encyclopedias listed on the library guide for History 200.
Depending on your approach and topic, these two online reference resources for literature may be useful to search.