Clinical trial protocol of the ASTER trial: a double-blind, randomized, placebo-controlled phase III trial evaluating the use of acetylsalicylic acid (ASA) for enhanced early detection of colorectal neoplasms - Tikk, Kaja; Czock, David; Haefeli, Walter E.; Kopp-Schneider, Annette; Brenner, Hermann (BioMed Central ; Springer, 2018)