The best database source for your research is RILM Abstracts of Music Literature. RILM is on the music databases page. Or, you can go directly to RILM here.
In addition to RILM, you might try JSTOR and Oxford Music Online. There may be others in the list that will work with your topic as well.
However, RILM is definitely the one to try. RILM will lead you to articles, books, book chapters, and dissertations in music history and criticism.
