3) Paul, W.D., and Antes, E.H.: Perforation of the esophagus caused by flexible gastroscope. Rev. Gastroenterol., 13: 23-25, 1946.
4) Hine, K.R., and Atkinson, M.: The diagnosis and management of perforations of esophagus and pharynx sustained during intubation of neoplastic esophageal strictures. Digestive Dis. Sci., 31: 571-573, 1986.