C#3-D3. Corey, Gerald. To the World's Bassoonists 4/2 (1974[75]): 4.

        c#
x x tr | o o o
   w    Bb

C#3-D3. Ewell, Terry B. (19 Feb. 95). Source unknown.

        c#
x x tr | o o o F
   w

C#3-D3. Popkin, Mark. In Klimko, Ronald. Bassoon Performance Practices and Teaching in the United States and Canada. Idaho: University of Idaho, 1974, p. 68.

        c#
x x tr | o o o
   w    Bb

C#3-D3. Timm, Everett LeRoy. The Woodwinds; Performance and Instructional Techniques. Boston: Allyn and Bacon, 1964, p. 172.

x x tr | o o x
   w        F#

Right index finger covers B hole and c# key?:

        c#
x x tr | x o o
   w

Heckel-System (German) Bassoon Trills and Shakes by Note Names