1. Zaino C, Beneventano T:Radiologic Exam of the Oropharynx and Esophagus. New York: Springer-Verlag, 1977, pp 141–180
2. Heeneman H, Brown DH: Senescent changes in and about the oral cavity and pharynx.J Otolaryngol 15(4):214–216, 1986
3. Zaino C, Jacobson H, Leparo H, Ozturk C:The Pharnygoesophageal Sphincter. Springfield: Charles C. Thomas, 1970, pp 136–169
4. Ekberg O, Wahlgren L: Dysfunction of pharyngeal swallowing. A cineradiographic investigation in 854 dysphagial patients.Acta Radiol Diagn 4:389–395, 1984
5. Lambert JR, Tepperman PS, Jimenez J, Newman A: Cervical spine disease and dysphagia.Am J Gastroenterol 76:35–40, 1981