D4. Allard, Maurice. Le Basson: Methode de basson (Paris: Gèrard Billaudot, 1975), p. 12. Allard's prefered fingering.
x x o | o o o Ab
D4. Allard, Maurice. Le Basson: Methode de basson (Paris: Gèrard Billaudot, 1975), p. 24. For fast passages.
x x o | o o o
D4. Corey, Gerald. "How to Make the French Bassoon `Work.'" The Journal of the International Double Reed Society 1 (May 1973): 39. "Most difficult note for tuning, resonance, and stability.
"This is my fingering for fast passages":
x x o | o o o Ab
"My strongest":
x x o | o o o Ab Eb
"English, good, but can go sharp":
x x o | o(x)x F