String Duos for Violin and Viola K423, 424 composed by Wolfgang Amadeus Mozart (1756-1791). Edited by Anja Bensieck. For Viola, Violin, String Duet. String Duos and Trios. Henle Music Folios. Pages: Score = VIII and 27 * K. 423 Vl = 8 * Va = 8 * K. 424 Vl = 8 * Va = 6. Softcover. 68 pages. G. Henle #HN624. Published by G. Henle (HL.51480624).