1. European Action on Anticoagulation, Central Facility, University of Manchester, Manchester, United Kingdom
2. Department of Clinical Biochemistry, Ribe County Hospital in Esbjerg, Esbjerg, Denmark
3. Bianchi Bonomi Hemophilia and, Thrombosis Centre, University and Instituto di Ricovero e, Cura a Carattere Scientifico, Maggiore Hospital, Milan, Italy