Macaulay A C, Commanda L E, Freeman W L, Gibson N, McCabe M L, Robbins C M, Twohig P L
Department of Family Medicine, McGill University, Herzl Family Practice Centre, SMBD Jewish General Hospital, 3755 Cote Ste Catherine, Montreal, Quebec, Canada H3T 1E2.
BMJ. 1999 Sep 18;319(7212):774-8. doi: 10.1136/bmj.319.7212.774.