1. University of Michigan, Ann Arbor, Michigan, USA
2. Harvard Pilgrim Health Care Institute, Boston, Massachusetts, USA
3. Vanderbilt University, Nashville, Tennessee, USA
4. National Library of Medicine, Bethesda, Maryland, USA
5. George Washington University, Washington, District of Columbia, USA
6. University of Illinois, Urbana-Champaign, Illinois, USA
7. Stanford University, Stanford, California, USA
8. University of Virginia, Charlottesville, Virginia, USA