1. The Permanente Medical Group, Oakland, California Kaiser Permanente Division of Research, Oakland, California Kaiser Permanente Sacramento Medical Center, Department of Emergency Medicine, Sacramento, California
2. University of California, San Diego, La Jolla, California
3. St. George’s University, School of Medicine, Grenada, West Indies
4. University of California, Davis, School of Medicine, Sacramento, California
5. Kaiser Permanente Division of Research, Oakland, California
6. University of California, Davis, School of Medicine, Sacramento, California Kaiser Permanente San Diego Medical Center, Department of Emergency Medicine, San Diego, California
7. The Permanente Medical Group, Oakland, California Kaiser Permanente San Rafael Medical Center, Department of Radiology, San Rafael, California
8. The Permanente Medical Group, Oakland, California Kaiser Permanente South Sacramento Medical Center, Department of Emergency Medicine, Sacramento, California
9. Kaiser Permanente San Diego Medical Center, Department of Emergency Medicine, San Diego, California
10. The Permanente Medical Group, Oakland, California Kaiser Permanente Division of Research, Oakland, California Kaiser Permanente Oakland Medical Center, Department of Emergency Medicine, Oakland, California