title: Pneumoperitoneum in perforated duodenal ulcer disease--a further look.
mesh_terms: D004381:Duodenal Ulcer / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D010439:Peptic Ulcer Perforation / Q000150:complications*; D011027:Pneumoperitoneum / Q000150:complications*