D+3. Bartolozzi,Bruno. New Sounds for Woodwind. London: Oxford University Press, 1971, p.31.

       c#
x x o | o o o
   w

D+3. Reinhard, Johnny. "The Microtonal Bassoon." The Double Reed 10/2 (Fall 1987): 42.

       c#
x x o | o o o
   w   Bb

D+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).

     Db c#
 x x o | o o o
Bb

Fingerings for microtones