Prediction of common bile duct stones in the earliest stages of acute biliary pancreatitis - van Santvoort, H. C.; Bakker, O. J.; Besselink, M. G.; Bollen, T. L.; Fischer, K.; Nieuwenhuijs, V. B.; Gooszen, H. G.; Erpecum, K. J. (Endoscopy, 2011)