Dotzauer Three Easy Duos Op. 114 (2 cellos)
#3780 Edited by Jeffrey Solow. Each part is in its own book. Don’t confuse “easy” with “for beginners.” Range stays within bass clef, 4th position, but includes more complex rhythms, lots of double stops that are not against open strings, sections in 3 sharps and flats. No idea why this volume is so expensive, but it does include a lot of music! I find this to be fun and practical sight-reading material as the range of notes is comfortable, but the intervals and rhythms really show you where your geography shortcomings lie.