Try Google Scholar. Advanced Search. The hamburger icon gets you there. Settings: Library Links to access online articles available at BU--View it @ BU
The most relevant results of BULS and GS will be on the first and second screens (in general).
For articles and books cited in Google Scholar that do not have links to JStor, etc., search for the name of the journal in BULS.
Remember to check a book's or article's bibliography (Works Cited, References) for more sources that may contribute additional insight into your topic.
Sometimes you will find the perfect or key book or article but you cannot figure out how to access it. Email me.
If there is a really great article but BU does not have the journal online, request the article from Interlibrary Loan. A scanned copy will be sent to your email.
If you are on campus, you can borrow print books via BU Libraries 2 GoUNLESS they are available online via HathiTrust--you will see the link.
Boston University Library Search -- BULS -- Advanced Search