1. Castell DO, Richter JE, Dalton CB (1987) Esophageal motility testing. Elsevier, New York
2. Code CF, Schlegel JF, Kelley ML, et al. (1960) Hypertensive gastroesophageal sphincter. Proc Mayo Clinic 35: 391
3. Ellis FH, Code CF, Olsen AM (1960) Long esophagomyotomy for diffuse spasm of the esophagus and hypertensive gastroesophageal sphincter. Surgery 48: 155
4. Eypasch E, Troidl H, Sommer H, Vestweber KH (1987) Long-term results of Troidl’s technique of endoscopic pneumatic dilatation for achalasia of the esophagus. Surg Endoscopy 1: 155–164
5. Eypasch E, DeMeester TR, Stein H, Vestweber KH, Barlow AP, Jenkins H (1989) Hypercontracting lower esophageal sphincter as a cause of dysphagia and chest pain. In: Skinner DB, Little AL, Ferguson MK (eds) Diseases of the esophagus. Futura, New York, pp 343–353