Secondary sources can be found through the UO Libraries catalog (listed below), which will help you to track down book-length studies, and databases that allow you to search the contents of hundreds of academic journals at once. "America: History and Life" indexes a wide range of U.S. history journals up to the present day, while JSTOR contains searchable full text of thousands of journals in every field, including history, but does not include the most recent years (usually the most recent six years) of issues.
These research guides will point you to other resources you can use, if you are finding those listed here inadequate.
