Selecting the best or most appropriate finding aid for identifying sources depends almost entirely on the context of your research project. There is no single database or web search interface that will work for every research context; instead, you'll need to match your specific research needs to a variety of options. 

1. Start with the information provided in tertiary sources! Look up specific titles of books in Primo, or journal titles (not article titles) in Primo's Journal Search. Use the vocabulary in the subject encyclopedia entries as search terms in databases.
2. Do an author search in Primo or a subject database. Which scholars are working on your topic? Many researchers will write about the same topic throughout their career. Searching by an author's name may help you gather additional information.
3. Mine the bibliographies and footnotes in other secondary sources. You may find one secondary source that is not quite right for your project; however, it may cite another scholarly source that would be just right!
4. When searching Primo or a database, pay attention to the subject headings in your results. You can use the vocabulary or click to do a new search for that heading. You'll be surprised at what you discover this way! 
5. Select the best sources, not just the most convenient sources. This may mean requesting a book or article from Summit or Inter-Library Loan, which can take about two to five days or more to arrive.