[1] CHARING CROSS & WESTMINSTER MED SCH, LONDON, ENGLAND
[2] MRC, EPIDEMIOL & MED CARE UNIT, LONDON WC1E 6AS, ENGLAND
[3] HOP HOTEL DIEU, PARIS, FRANCE
[4] OSPED RIUNITI BERGAMO, I-24100 BERGAMO, ITALY
[5] UNIV CATTOLICA SACRO CUORE, I-00168 ROME, ITALY
[6] UNIV FEDERICO 2, NAPLES, ITALY
[7] HAREFIELD HOSP, HAREFIELD, MIDDX, ENGLAND