1. Birmingham VA Health Care System Birmingham Alabama USA
2. University of Alabama at Birmingham School of Medicine Birmingham Alabama USA
3. University of California David Geffen School of Medicine Los Angeles California USA
4. Michigan Medicine Department of Anesthesiology Ann Arbor Michigan USA
5. VA Center for Clinical Management Research Ann Arbor Michigan USA
6. University of Alabama at Birmingham School of Public Health Birmingham Alabama USA
7. VA Salt Lake City Health Care System Salt Lake City Utah USA
8. University of Utah School of Medicine Salt Lake City Utah USA