A+3. Bartolozzi, Bruno. New Sounds for Woodwind. London: Oxford University Press, 1971, p. 31.
x x x | x x o c a
A+3. Reinhard, Johnny. "The Microtonal Bassoon." The Double Reed 10/2 (Fall 1987): 42.
x x x | x x o Ab
A+3. Vigder, Scott. "A Table of Quarter-Tone Fingerings for the Bassoon," The Double Reed 4/2 (October 1981): 44. These fingerings were extracted from Sergio Penazzi's Metodo per Fagotto (Edizoni Suvini Zerboni-Milano, 1971).
x x x | x x o Ab