Geographical variability and environmental risk factors in inflammatory bowel disease
Siew C Ng, Charles N Bernstein, Morten H Vatn, Peter Laszlo Lakatos, Edward V Loftus, Curt Tysk, Colm O'Morain, Bjorn Moum, Jean-Frédéric Colombel, on behalf of the Epidemiology and Natural History Task Force of the International Organization of Inflammatory Bowel Disease (IOIBD)
Gut Apr 2013, 62 (4) 630-649; DOI: 10.1136/gutjnl-2012-303661