Letter: Upper gastrointestinal endoscopy.
D001466:Barium Sulfate; D003258:Consumer Behavior; D004064:Digestive System; D004724:Endoscopy; D004945:Esophagoscopy; D005773:Gastroscopy; D006801:Humans; D011795:Surveys and Questionnaires
D001466:Barium Sulfate