PARLAK, Erkan, et al. “The Efficacy of 5-ASA Preparations in Prevention of Postoperative Recurrence of Crohn’s Disease (Retrospective Assesstment)”. Turkish Journal of Gastroenterology, vol. 10, no. 3, Jan. 1999, pp. 276-9, https://www.turkjgastroenterol.org/index.php/tjg/article/view/1002.