1 President, Bucerius Law School, Jungiusstrasse 6, 20355, Hamburg, Germany.
2 President, American Friends of the Alexander von Humboldt Foundation, 1101 17th Street NW, Suite 603, Washington, DC, 20036, USA.
3 President, Alexander von Humboldt-Stiftung, Jean-Paul-Strasse 12, 53173, Bonn, Germany.
4 University of Pennsylvania, Department of Earth and Environmental Science and Department of Chemistry, 251 Hayden Hall, 240 South 33rd Street, Philadelphia, PA, 19104-6316, USA.