1. BSCS Science Learning, Colorado Springs, Colorado, USA
2. School of Education and Social Policy, Northwestern University, Evanston, Illinois, USA
3. Boston College, Boston, Massachusetts, USA
4. Charles A. Dana Center, University of Texas, Austin, Texas, USA
5. University of Michigan, Ann Arbor, Michigan, USA
6. University of Colorado, Boulder, Colorado, USA
7. Concolor Research, Boulder, Colorado, USA
8. College of Education, University of Texas, Austin, Texas, USA
9. University of Massachusetts, Amherst, Massachusetts, USA