| Institution: | (1) The Astronomical Institute, Utrecht;(2) Laboratory for Extraterrestrial Physics-NASA/GSFC, Greenbelt, Maryland;(3) Jet Propulsion Laboratory, California Institute of Technology, 91103 Pasadena, Calif., USA;(4) National Aerospace Laboratory, Amsterdam;(5) Physics Laboratories, University of Utrecht, Utrecht, The Netherlands;(6) Astronomical Observatory, Trieste;(7) The University of Texas, Dallas;(8) Astronomical Institute, Ondrejov, Czechoslovakia;(9) Space Research Laboratory, Utrecht;(10) Air Force Geophysics Laboratory, Bedford, Mass.;(11) Institut d'Astrophysique, Université de Liège, Cointe-Ougrée, Belgium |
