1. University of Western Ontario
London, OntarioCanada
2. Wayne State University
Detroit, MichiganUSA
3. Gold Coast Hospital
Gold Coast, QueenslandAustralia
4. Rikshospitalet, University of Oslo
OsloNorway
5. Cardiovascular Associates PC
Birmingham, AlabamaUSA
6. Pfizer Inc
New York, New YorkUSA
7. Pfizer Inc
New York, New York, USA at the time the study was conducted
8. University of Oxford
OxfordUK