[1] Imperial Canc Res Fund, Med Stat Grp, Oxford, England
[2] Inst Hlth Sci, Ctr Stat Med, Oxford, England
[3] Univ Bristol, MRC, Hlth Serv Res Collaborat, Bristol, Avon, England
[4] London Sch Hyg & Trop Med, London WC1, England
[5] Family Hlth Int, Chapel Hill, NC USA
[6] Univ N Carolina, Sch Med, Chapel Hill, NC USA
[7] Thomas C Chalmers Ctr Systemat Reviews, Ottawa, ON, Canada
[8] Amer Coll Physicians, Amer Soc Internal Med, Philadelphia, PA USA
[9] Nord Cochrane Ctr, Copenhagen, Denmark
[10] Tom Lang Commun, Lakewood, CO USA