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