Use relevant bibliographies.
Once you have found a good article or book on your topic, look at the references that author cites. You'll probably find many sources that you can use. The author(s) may cite archival collections and primary source documents as well as scholarly books and articles.
Search historically.
Spelling, word choice, and geographic names may have been different during the time period you are researching. So if you are searching for primary source documents, you may need to use these older spellings and terms to find relevant sources.
Use subject headings (in Tripod) to browse for books on a topic.
If you find a book in Tripod that looks relevant to your topic, click on the Subjects links to find similar books. For example, here's a list of books with the subject Tobacco -- History.
See how often a particular article or author has been cited
Citations provide one clue to an article or author's level of influence on their field. Try looking up an article, book, or author in Google Scholar to see how often they've been cited.
