A comparative study of standard ERCP catheter and hydrophilic guide wire in the selective cannulation of the common bile duct - Katsinelos, P; Paroutoglou, G; Kountouras, J; Chatzimavroudis, G; Zavos, C; Pilpilidis, I; Tzelas, G; Tzovaras, G (Endoscopy, 2008)