Reference books and reference sources are used to locate definitions, facts, and background information.
Good researchers do not read reference books from start to end.
Instead, they consult reference books and reference sources for specific information needed to define and understand key concepts, theories, and historical and biographical events.
Below are two good databases to locate Reference Sources for music research:
Oxford Music Online
CREDO Reference
WHAT
Use the Reference Sources Database listed above to introduce your Musical Genre and define it.