1. The Vascular Laboratories, Department of Surgery, Good Samaritan Hospital, Cincinnati, Ohio, USA
2. The Vascular Laboratory, Harper-Grace Hospitals, Detroit, Michigan, USA
3. Surgical Education, Roanoke Memorial Hospitals, Roanoke, Virginia, USA
4. Peripheral Vascular Laboratory, Latter Day Saints Hospital, Salt Lake city, Utah, USA
5. Vascular Surgery, Temple University, Philadelphia, Pennsylvania, USA
6. Medical College of Georgia, Augusta, Goergia, USA