Clarinet Fundamentals 3: Intonation by Reiner Wehle. Schott, 2008, PB, 112 pages. This book explains both the theory and practice of intonation (in English and German) and has many intonation exercises in duet form with a few as trios. This is followed by 29 pages of examples from the orchestral repertoire of (mostly) two clarinets playing in harmony, octaves, and unison. (C1309)