Cita APA (7a ed.)

American College of Surgeons. (1991). American College of Surgeons. 1991 cumulative supplement to the 1989 yearbook. American College of Surgeons.

Cita Chicago Style (17a ed.)

American College of Surgeons. American College of Surgeons. 1991 Cumulative Supplement to the 1989 Yearbook. Chicago: American College of Surgeons, 1991.

Cita MLA (9a ed.)

American College of Surgeons. American College of Surgeons. 1991 Cumulative Supplement to the 1989 Yearbook. American College of Surgeons, 1991.