1. editor. 1966. Morris' human anatomy. 12th Ed. New York: McGraw-Hill. p 685.
2. 1988. Compendium of human anatomic variation. Baltimore: Urban and Schwarzenberg. p 65-66.
3. editor. 1985. Gray's anatomy. 13th Ed. Philadelphia: Lea & Febiger. p 679.
4. editor. 1980. Sicher's oral anatomy. 7th Ed. St. Louis: C.V. Mosby. p 361, 469.