[1] UNIV WALES COLL CARDIFF,DEPT ANAESTHET,CARDIFF,WALES
[2] BRADFORD ROYAL INFIRM,BRADFORD,ENGLAND
[3] UNIV AUTONOMA BARCELONA,INST MUNICIPAL INVEST MED,DEPT PHARMACOL & TOXICOL,BARCELONA,SPAIN
[4] UNIV HOSP GENEVA,DIV CLIN PHARMACOL & PAIN CLIN,GENEVA,SWITZERLAND
[5] UNIV COLOGNE,DEPT ANAESTHESIOL & OPERAT INTENS CARE MED,COLOGNE,GERMANY
[6] ANALGESIC DEV LTD,NEW YORK,NY