C+5. Bartolozzi, Bruno. New Sounds for Woodwind. London: Oxford University Press, 1971, p. 32.

   eb trill key
x o o | o o o
 c

C+5. Reinhard, Johnny. "The Microtonal Bassoon." The Double Reed 10/2 (Fall 1987): 42.

 o o o | x x o F
d c

or:
    Eb?
x o o | x x o F
 c     Bb  plus Ab-Bb trill key

C+5. Vigder, Scott. "A Table of Quarter-Tone Fingerings for the Bassoon," The Double Reed 4/2 (October 1981): 45. These fingerings were extracted from Sergio Penazzi's Metodo per Fagotto (Edizoni Suvini Zerboni-Milano, 1971).

    Eb
x o o | x x o F
 c     Bb

Fingerings for microtones