[1] HARVARD UNIV,SCH PUBL HLTH,TECHNOL ASSESSMENT GRP,BOSTON,MA 02115
[2] VET ADM MED CTR,BOSTON,MA
[3] UNIV TEXAS,MD ANDERSON HOSP & TUMOR INST,CTR CANC,DEPT BIOMATH,HOUSTON,TX 77030
[4] MAYO CLIN & MAYO FDN,CANC CTR STAT E12,ROCHESTER,MN 55905
[5] UNIV LONDON LONDON SCH HYG & TROP MED,DEPT EPIDEMIOL & POPULAT SCI,LONDON WC1E 7HT,ENGLAND
[6] HARVARD UNIV,SCH PUBL HLTH,BOSTON,MA 02115