TY - JOUR AU - Heaton, K W TI - Bristol Stool Chart and Bristol Stool Form Scale JO - BMJ VL - 338 PY - 2009 DO - 10.1136/bmj.b831 SP - b831 N1 - Leserbrief zu McCallum IJ, Ong S, Mercer-Jones M. Chronic constipation in adults. ER -