Do not jump straight to Google when doing research! Books still hold valuable information, some of which you may not find online.
When researching you should not feel pressured to read the entire book immediately if your subject of study only appears in one chapter. Make your research manageable and direct yourself to the table of contents or index to find your topic.
Thematic catalogues in music: an annotated bibliography by 
Sourcebook for research in music by 
Music analyses: an annotated guide to the literature by 
Music reference and research materials: an annotated bibliography, 5th ed. by 
Information sources in music by 
Information on music: a handbook of reference sources in European languages by 
Reader's guide to music: history, theory, criticism by Analyses of nineteenth- and twentieth-century music: 1940-1984 by 
