A Prospective Randomized Trial of Teflon Versus Polyethylene Stents for Distal Malignant Biliary Obstruction - van Berkel, A M; Boland, C; Redekop, W K; Bergman, J J G H M; Groen, A K; Tytgat, G N J; Huibregtse, K (Endoscopy, 1998)