Development of the Harvey-Bradshaw Index-pro (HBI-PRO) Score to Assess Endoscopic Disease Activity in Crohn’s Disease. - Zittan, Eran; Kabakchiev, Boyko; Kelly, Orlaith B.; Milgrom, Raquel; Nguyen, Geoffrey C.; Croitoru, Kenneth; Steinhart, A. Hillary; Silverberg, Mark S. (Journal of Crohn's & Colitis, 2017)