Güller U, Warschkow R, Ackermann CJ, Schmied BM, Cerny T, Ess S. Lower hospital volume is associated with higher mortality after oeosophageal, gastric, pancreatic and rectal cancer resection: a Swiss population-based analysis. Swiss Med Wkly. 2017;147:w14473. https://doi.org/10.4414/smw.2017.14473
Birkmeyer JD, Siewers AE, Finlayson EV, Stukel TA, Lucas FL, Batista I, et al. Hospital volume and surgical mortality in the United States. N Engl J Med. 2002;346(15):1128–37. doi:.https://doi.org/10.1056/NEJMsa012337