IV. Score in a series:  Use Turabian 11.16, "Book in a Series."
(Note: DO NOT underline or italicize the series title)
 

e. With a parallel title:

Gassman, Florian Leopold.  Zwei Streichtrios / Two String Trios.  Edited by Wolfgang
        Sawodny.  Hortus Musicus, 247.  Kassel: Bärenreiter, 1988.  Parts.