Oxford Music Online combines three major print dictionaries: Grove Music Online, Oxford Companion to Music, and Oxford Dictionary of Music.
Grove articles display first (because they are the best). To view results from the other two, click the additional link once you see the results.
Browse in the reference section on the 1st floor in the 780's. Or search one of the multi-disciplinary encyclopedia databases (helpful if you need to know more history aside from music).
Music scholarship is built primarily on what has already been researched, not on what is newly discovered (unlike the sciences). Sometimes, an older seminal work is referred to and counted on even as many years pass.
Incorporating subject terms into your search--either by clicking them to do new searches or adding them as keywords--will help you find more sources than you did on your own keywords.
If you look for articles before you've narrowed as much as you can, you'll likely choose many interesting articles that are sort of about the same thing--but not really about the same one more specific thing. That makes writing a paper more difficult.
When researching historical music topics, you may find a need to locate primary sources. These are sometimes re-published in books and sometimes available digitized online at museum and archive websites.
There is rarely a need to look for non-scholarly web-published content in historical music research. If you are having trouble finding a historical topic in the resources linked above, don't hesitate to contact the librarian!
You answer these three questions every time you use a source, whether you know it or not. As you choose sources for everything from 1st-year courses to major-specific research courses to real life, notice how you answer these questions to ensure your sources are really meeting your needs.
Quick reference for the three questions:
Vogel Library, Wartburg College | 100 Wartburg Blvd, Waverly, IA, 50677 | Phone: 319-352-8500 | Email: firstname.lastname@example.org