Wolters FL, Zeijl GV, Sijbrandij J, Wessels F, O’Morain C, Limonard C, Russel MG, Stockbrügger RW. Internet-based data inclusion in a population-based European collaborative follow-up study of inflammatory bowel disease patients: Description of methods used and analysis of factors influencing response rates. World J Gastroenterol 2005; 11(45): 7152-7158 [PMID: 16437663 DOI: 10.3748/wjg.v11.i45.7152]