1. The Johns Hopkins University Applied Physics Laboratory Laurel MD USA
2. Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA
3. Department of Physical and Chemical Sciences University of L'Aquila L'Aquila Italy
4. Consorzio Area di Ricerca in Astrogeofisica L'Aquila Italy
5. Mining and Geological Survey of Hungary Budapest Hungary
6. School of Physics and Astronomy, University of Minnesota Minneapolis MN USA
7. Department of Astronomy and Space Science Kyung Hee University Yongin South Korea
8. Department of Physics and Institute for the Study of Earth, Oceans, and Space University of New Hampshire Durham NH USA