String Trio Cello,Viola,Violin - Level 4 - Digital Download SKU: A0.1472851 By Andrés LLona. By Andrés LLona. 21st Century,Classical,Contemporary. 22 pages. Andres LLona #1050481. Published by Andres LLona (A0.1472851). This is a Contemporary music of a String Trio: Violin Viola and Chello. The main idea of ??this musical piece is that it is progressing smoothly in the early stages, but I found that this is an accelerated approach and that I have to carefully consider the steps, if that is not necessary it is precise and accurate.