Stamitz, Carl Philipp
Sestetto per il Viola da Gamba, Violino, Viola, 2 corni, è violoncello in E flat major
D-SWl mus. 5244; D-B (coll. Klingenberg)
The viola da gamba part is notated in D, one semitone below the others, probably to allow it to be played with greater string tension.
David J. Rhodes, The viola da gamba, its repertory and practitioners in the late eighteenth century, Chelys, vol. 31 (2003), pp. 36-63