J. Borgosz, B. Kupczak-Wiśniowska, B. Podsiadło, and B. Serzysko, “Role of endoscopic retrograde cholangiopancreatography in the diagnosis of choledocholithiasis”, Piel21w, vol. 15, no. 4(57), pp. 48 – 52, Apr. 2017, doi: 10.1515/pielxxiw-2016-0037.