Chatoor D, Emmnauel A (2009). "Constipation and evacuation disorders". Best Pract Res Clin Gastroenterol. 23 (4): 517–30. doi:10.1016/j.bpg.2009.05.001. PMID19647687.
Wilson, Dodd (1990). "85". In Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.). Clinical Methods: The History, Physical, and Laboratory Examinations. Boston: Butterworths. ISBN9780409900774.
Chatoor D, Emmnauel A (2009). "Constipation and evacuation disorders". Best Pract Res Clin Gastroenterol. 23 (4): 517–30. doi:10.1016/j.bpg.2009.05.001. PMID19647687.