1. Pope CE: Motor disorders (of the esophagus). Gastrointestinal Disease. MH Sleisenger, JS Fordtran, (eds.) Saunders, Philadelphia, 1973, pp 107?108
2. Garrett JM, Winklemann RK, Schlegel JF: The course of esophageal deterioration in scleroderma. Mayo Clin Proc 46:92?96, 1971
3. Creamer B, Anderson HA, Code CF: Esophageal motility in patients with scleroderma and related diseases. Gastroenterologia 86:763?775, 1956.
4. Atkinson M, Summerling MD: Oesophageal changes in systemic sclerosis. Gut 7:402?408, 1966
5. Winklemann RK: Classification and pathogenesis of scleroderma. Mayo Clin Proc 46:83?91, 1971.