1. Pediatric development: gastrointestinal;Batchelor,2014
2. Administration on Aging. Aging statistics. 2014. Available at: http://www.aoa.gov/Aging Statistics/. Retrieved July 30, 2014.
3. Facts about IBS. International Foundation for Functional Gastroin-testinal Disorders.
4. Mayo Clinic. Inflammatory Bowel Disease (IBD). 2014. Available at: http://www.mayoclinic.org/diseases-conditions/ irritable-bowel-syndrome/basics/symptoms/con-20024578. Retrieved February 7, 2014.
5. Aging biology and geriatric clinical pharmacology;McLean;Pharmacol Rev,2004