Needle-knife papillotomy as a second step procedure - ÇETİN, Celalettin and BAĞCI, Sait and UYGUN, Ahmet and GÜLŞEN, Mustafa and KADAYIFÇI, Abdurrahman and KARAEREN, Necmettin and DAĞALP, Kemal (Turkish Journal of Gastroenterology, 2000)