1. Seeley RR, Stephens TD, Tate P (Eds). Digestive system. In: Anatomy and physiology. 2nd Ed. St. Louis: Mosby Year Book, 1992: 773–781
2. Tortora GJ, Anagnostakos NP (Eds). The digestive system. In: Principles of anatomy and physiology. 5th Ed. New York: Harper and Row, 1987: 595–600
3. Cate TAR (Ed.). Oral mucosa. In: Oral histology. 3rd Ed. St. Louis: Mosby, 1989: 341–381
4. Thibodeau GA, Patton KT (Eds). The digestive system. In: The human body in health and disease. 1st Ed. St. Louis: Mosby, 1992: 405–411
5. Fitzpatrick TB, Eisen AZ, Wolff K, et al. (Eds). Disorders of the mucocutaneous integument. In: Dermatology in general medicine. 4th Ed. New York: McGraw Hill, 1993: 1355–1417