Am. J. Gastroenterol., 91: 1226-1231, 1996.
18. KING, S., CHAMBERS, C. T., HUGUET, A., MACNEVIN, R. C., MCGRATH, P. J., PARKER, L., MACDONALD, A. J.: The epidemiology of chronic pain in children and adolescents revisited: Asystematic review. Pain, 152: 2729-2738, 2011.