Assessment of the multiple components of the variability in the adenoma detection rate in sigmoidoscopy screening, and lessons for training - Fracchia, M.; Senore, C.; Armaroli, P.; Ferraris, R.; Placido, R. Di; Musso, A.; Turco, D.; Bellisario, C.; Baldi, I.; Segnan, N. (Endoscopy, 2010)