1. The seasonal incidence of complications of peptic ulcer;Ahmed;Ann Intern Med,1963
2. Seasonal incidence of perforated ulcer;Bradley;Am J Surg,1966
3. The seasonal incidence of peptic ulcer activity—fact or fancy? With special reference to gastrointestinal hemorrhage;Gardiner;Am J Gastroenterol,1966
4. The calendar and duodenal ulcer;Hall;Gastroenterology,1972
5. Seasonal periodicity of perforated gastric ulcer;Christensen;Dan Med Bull,1988