Wenger N S, Rosenfeld K
Department of Medicine, Division of General Internal Medicine and Health Services Research, University of California, Los Angeles, 911 Broxton Plaza, Los Angeles, CA 90095-1736, USA.
Ann Intern Med. 2001 Oct 16;135(8 Pt 2):677-85. doi: 10.7326/0003-4819-135-8_part_2-200110161-00006.