The improtance of the sphincterotomy in the diagnosis of periampullary carcinoma: analysis of 664 patients who underwent ERCP - BAYRAKTAR, Yusuf; ÖZGENÇ, Ahmet; ÖZDEMİR, Arif; ÖKSÜZOĞLU, Gürol; ARSLAN, Serap; COŞKUN, Teoman; UZUNALİMOĞLU, Bedri (Turkish Journal of Gastroenterology, 1997)