The Garland Encyclopedia of World Music, by Bruno Nettl and Ruth M. Stone, advisory editors, James Porter and Timothy Rice, founding editors
October 1, 2004- PDF https://www.jstor.org/stable/40374497
Baker's Dictionary of Opera, edited by Laura Kuhn
October 1, 2000- PDF https://www.jstor.org/stable/40374412
- PDF https://www.jstor.org/stable/40374575
- PDF https://www.jstor.org/stable/40373848