Common encyclopedias (such as Grove), do not need to be included in your Bibliography. Others should be cited as below.
Wolff, Christoph and Walter Emery. "Bach, Johann Sebastian." Grove Music Online. Edited by Deane Root. Accessed April 27, 2019. https://doi.org/10.1093/gmo/9781561592630.article.6002278195.
1. Christoph Wolff and Walter Emery, “Bach, Johann Sebastian,” Grove Music Online, ed. Deane Root, accessed April 27, 2019, https://doi.org/10.1093/gmo/9781561592630.article.6002278195.
Grove (Print Version)
Bibliography
Neighbour, O.W. "Schoenberg, Arnold." The New Grove Dictionary of Music and Musicians. Edited by Stanley Sadie and John Tyrrell. London: Macmillan, 2001. xvii: 745.
Notes
1. O.W. Neighbour, "Schoenberg, Arnold," The New Grove Dictionary of Music and Musicians, eds. Stanley Sadie and John Tyrell (London: Macmillan, 2001), xvii: 745.
Other Reference Works (Encyclopedias, Dictionaries, etc.)
Some Encyclopedias list the author of a particular article (these are considered "signed entries") whereas most others do not list the author ("unsigned entries").
Common encyclopedias (such as Grove), do not need to be included in your Bibliography. Others should be cited as below.
Author Last Name, Author First Name. "Title of Article." Title of Encyclopedia. Publication Location: Publisher, Year of Publication.
Die Musik in Geschichte und Gegenwart. Edited by Ludwig Finscher. 2nd ed. Kassel: Bärenreiter, 1994-2007.
The Garland Encyclopedia of World Music. Edited by Bruno Nettl and Ruth Stone. New York: Garland, 1998-2002.
Kubik, Gerhard and Artur Simon. "Afrika südlich der Sahara." In Die Musik in Geschichte und Gegenwart, edited by Ludwig Finscher, 2nd ed. (Kassel: Bärenreiter, 1994-2007), s.v. "Afrika südlich der Sahara."
1. Reinhard Wiesend, "Baccanale," Die Musik in Geschichte und Gegenwart (Kassel: Bärenreiter-Verlag, 1994), 1105-7.
2. Encyclopedia Britannica, 15th ed. (1980), s.v. "salvation."
3. Ward Keeler, "Burma," in The Garland Encyclopedia of World Music, eds. Terry E. Miller and Sean Williams (New York: Garland, 1998). (v 4 of 10)
4. Die Musik in Geschichte und Gegenwart, ed. Ludwig Finscher, 2nd ed. (Kassel: Bärenreiter, 1994-2007), s.v. "Afrika südlich der Sahara."
For "signed entries"
5. Kubik, Gerhard and Artur Simon. "Afrika südlich der Sahara." In Die Musik in Geschichte und Gegenwart, ed. Ludwig Finscher, 2nd ed. (Kassel: Bärenreiter, 1994-2007), s.v. "Afrika südlich der Sahara." (v 1 or 20)