From the Bassoon-Family Fingering Companion by Terry B. Ewell - Groeling, Charles R. "Cultivating Bassoonists." The Instrumentalist 47/1 (August 1992): 50. Corey, Gerald E. "How to Improve Your Tuning on the Bassoon." The Journal of the International Double Reed Society 8 (1980): 32. Cooper p. 204.