Heckel C#4-D#4

C#4-D#4. Christlieb, Don. Pictoral Fingerings for Bassoon. Published by author, 1966, p. 25.

x x tr | o x x F
   c#

C#4-D#4. Ewell, Terry B. (28 April 1995). Common trill.

x x tr | o o o
   c#
   D

C#4-D#4. Timm, Everett LeRoy. The Woodwinds; Performance and Instructional Techniques. Boston: Allyn and Bacon, 1964, p. 174.

x x tr | o(x)(x)(F)
   c#
   D

x x x | x x x F
   c#          Ab-tr

x x x | x x x Ab-tr
   c#      F#