[1] UNIV MANCHESTER,ARTHRITIS & RHEUMATISM COUNCIL,EPIDEMIOL RES UNIT,SLOPFORD BLDG,MANCHESTER M13 9PT,LANCS,ENGLAND
[2] UNIV LONDON LONDON HOSP,COLL MED,DEPT EPIDEMIOL,LONDON E1 2AD,ENGLAND
[3] MCQUARIE UNIV,STAT LAB,SYDNEY,AUSTRALIA
[4] W MIDDLESEX HOSP,DEPT RHEUMATOL,LONDON,ENGLAND