1. Summers B. Pneumoperitoneum associated with artificial ventilation. BMJ 1979;1(6177):1528–1530.
2. Cancarini GC, Carli O, Cristinelli MR, Manili L, Maiorca R. Pneumoperitoneum in peritoneal dialysis patients. J Nephrol 1999;12:95–99.
3. Bryant L, Wiot J, Kloecker R. A study of the factors affecting the incidence and duration of postoperative pneumoperitoneum. Surg Gynecol Obstet 1963;117:145–150.
4. Bevan PG. Incidence of postoperative pneumoperitoneum and its significance. BMJ 1961;2:605–609.
5. Harrison I, Litwer H, Gerwig W. Studies on the incidence of postoperative pneumoperitoneum. Ann Surg 1957;145:591–594.