Development of the Paris definition of early Crohn's disease for disease-modification trials: results of an international expert opinion process. by Peyrin-Biroulet, L, Billioud, V, D'Haens, G, Panaccione, R, Feagan, B, Panés, J, Danese, S, Schreiber, S, Ogata, H, Hibi, T, Higgins, P, Beaugerie, L, Chowers, Y, Louis, E, Steinwurz, F, Reinisch, W, Rutgeerts, P, Colombel, J, Travis, S, Sandborn, W