IV. Score in a series:  Use the same style as a "Book in a Series."
(Note: DO NOT underline or italicize the series title)  following MLA 8

c. Including editor:

Haydn, Michael.  Streichquartette Nr. 5 in F-Dur. Edited by Helmut Zehetmair, Doblinger, 1972.  Diletto Musicale, nr. 335.  Parts.