S. Saint, D. Christakis, S. Saha, J. Elmore, D. Welsh, P. Baker, and T. Koepsell. Journal of general internal medicine : official journal of the Society for Research and Education in Primary Care Internal Medicine, 15 (12):
881-884(December 2000)LR: 20061115; PUBM: Print; JID: 8605834; ppublish.
P. Royle, and N. Waugh. BMC medical research methodology, (July 2005)LR: 20061115; PUBM: Electronic; DEP: 20050723; JID: 100968545; 2005/02/05 received; 2005/07/23 accepted; 2005/07/23 aheadofprint; epublish.
P. Royle, L. Bain, and N. Waugh. BMC medical research methodology, 5 (1):
2(January 2005)LR: 20061115; PUBM: Electronic; DEP: 20050108; JID: 100968545; 2004/08/11 received; 2005/01/08 accepted; 2005/01/08 aheadofprint; epublish.