1. Occidental College, Los Angeles, CA, USA.
2. Scripps Institution of Oceanography, La Jolla, CA, USA.
3. University of Bonn, Bonn, Germany.
4. California Institute of Technology, Pasadena, CA, USA.
5. Rutgers University, New Brunswick, NJ, USA.
6. Temple University, Philadelphia, PA, USA.
7. Washington State University, Pullman, WA, USA.