Maryland, University, College Park Florida, University, Gainesville, Fla. Max-Planck-Institut fuer Extraterrestrische Physik, Garching, West CNR, Gruppo Nazionale per l'Astronomia, Rome, Italy CNR, Gruppo Nazionale per l'Astronomia, Catania, Italy CNR, Gruppo Nazionale per l'Astronomia, Naples, Italy Universidad Nacional Autonoma de Mexico, Ensenada Univ. Nacional Autonoma de Mexico, Ensenada Instituto di Fisica Cosmica, Milano, Italy New South Wales, University, Kensington, Australia Polska-Akademia Nauk, Centrum Astronomiczue, Torun, Poland Russian Academy of Science, Niznij Arhyz, Russia Osservatorio Astronomico di Padova, Asiago, Italy Moskovskii Gosudarstvennyi Universitet, Moscow, USSR Australia Telescopes National Faciltiy, Epping, Australia Australian Telescope National Facility, Epping, Australia Canadian Inst. for Theoretical Astrophysics, Canada Nuffield Radio Astronomy Observatory, Jodrell Bank, England Observatoire Astronomique du Mont Megantic, Montreal, Canada Observatorio Astronomico de Cerro Tololo, La Serena Tata Institute of Fundamental Research, Bombay Tata Inst. of Fundamental Research, Poona, India Tata Institute of Fundamental Research, Bangalore, India AT&T Bell Telephone Laboratories, Inc., Murray Hill Landessternwarte Koenigstuhl, Heidelberg, Germany Landessternwarte, Konigstuhl, Heidelberg, Germany Goddard Institute for Space Studies, New York CSIRO, Australia Telescope National Facility, Epping Canadian Institute for Theoretical Astrophysics, Canada Tata Institute of Funadamental Research, Bombay, India Beijing Normal University, Beijing, People's Republic of China Nanjing University, Nanjing, People's Republic of China Tata Institute for Fundamental Research, Bombay, India Max-Planck-Institut fuer Astronomie, Heidelburg, Germany Max-Planck-Institute fuer Astronomie, Heidelburg, Germany Max-Planck-Institut fur Astronomie, Heidelberg, Germany Max-Planck-Institut fuer Physik und Astrophysik, Muenchen, Germany Joint Institute for Laboratory Physics, Boulder, Colo. Max-Planck-Inst. fuer Physik und Astrophysik, Garching, Germany Max-Planck Inst. fuer Astrophysik, Garching, Germany Max-Planck Institute fuer Extraterrestriche Physik, Garching, Germany Max-Planck-Institute fuer Exrtraterrestrische Physik, Garching, Germany Max-Planck Institut fuer extraterrestriche Physik, Garching, Germany Max-Planck-Institut fuer Extraterrestriche Physik, Garching, Germany Max-Planck-Institut fuer Extraterrestrishce Physik, Garching, Germany Max-Plack-Institut fur Extraterrestrische Physik, Garching, Germany Max-Planck-Institut fuer extraterrestrische Physik, Garching, Germany Max-Planck-Institut fuer Extraerrestrische Physik, Garching, Germany Max-Planck-Inst. fuer Extraterrestrische Physik, Berlin, Germany Max-Planck-Inst. fuer Extraterrestrische Physik, Muenchen, Germany Univ. Nacional Autonoma de Mexico, Mexico Max-Planck-Institut fuer Astrophysik, Gar Max-Planck-Institut fuer Astrophysik, Garching Astronomiches Rechen-Institut, Heidelberg, Germany CSIC, Granada, Spain University of Sydney, NSW, Australia Vanderbilt Univ. Cambridge Univ. York Univ., North York, Canada Nice, Universite Liege, Universite Tokyo, University Montrel, Universite Wyoming, University Trieste, Universita Bologna, Universita Space Research Inst., Moscow, Russia University of Illinois at Urbana-Champaign, Urbana, IL, US NASA, Goddard Institute for Space Studies, New York Max Planck Institut fuer Kernphysik, Heidelberg, Germany Paris VII, Universite, Meudon, France Indiana University, Bloomington Montreal, Univ. Montreal Univ. Milano Univ. Salamanca, Universidad, Spain Barcelona, Universidad, Spain Konkoly Observatory, Budapest, Hungary Observatoire du Mont Megantic, Quebec CNR, Istituto di Fisica Cosmica, Italy Stanford University, Stanford, CA, US Lecce, Universita, Lecce La Laguna, Universidad, Spain Lick Observatory Rice University, Houston, TX, US Haifa, University, Haifa, Israel Pahlavi University, Shiraz, Iran Kagoshima University, Kagoshima, Japan Tohoku-Gakuin University, Tagajo, Japan Tohuku University, Sendai, Japan Dokkyo University, Soka, Japan California, University, Davis, CA Osaka University, Osaka, Japan Tokyo, University, Mitaka, Japan Boston College, Newton, MA, US Basel, Universitaet, Switzerland Basel Universitaet, Switzerland Tuebingen, Universitaet, Germany Princeton University, New Observatory Colgate University, Ithaca, N.Y. Tours, Universite, France Drake Univ., Des Moines, IA, US Missouri, University, St. Louis California, University, Santa Cruz Michigan, University, Ann Arbor, Mich. Cornell University, Ithaca, NY California, University, Riverside Jena, Univ.-Sternwarte, Germany Gifu University, Japan Montreal, Universite Montreal Montreal, Universiite, Montreal Montreal Universite, Montreal Montreal, Universite, Montreal Osaka Univ., Toyonaka, Japan Lodz Univ., Poland Pisa, Universita, Italy Toronto Univ., Canada York Univ., Canada Milan, Universita Milano, Universita Firenze, Universita Milan, Universita Milano, Universita Firenze, Universita Pisa, Universita Roma, Universita Pisa, Universita Roma, Universita Genova, Universita Padova, Universita Leeds, University Texas University Toyama Univ., Japan Tokyo Univ., Tokyo, Japan Tokyo Univ., Tokyo, Japan Kinki Univ., Osaka, Japan Nagoya University, Japan Nagoya University, Toyokawa, Japan Nagoya University, Toyokawa, Japan Kobe Univ., Japan Tokyo Univ., Japan Kumamoto Univ., Japan Gifu Univ., Japan Toho Univ., Chiba, Japan Toho Univ., Chiba, Japan Tokyo Univ., Mitaka, Japan Tokai Univ., Kanagawa, Japan Gdansk Univ., Poland Queen's Univ., Ontario, Canada Queens Univ., Ontario, Canada York University, Ontario, Canada Toledo Univ., OH Univ. of Tokyo, Tokyo, Japan Tartu Univ., Tartu, Estonia Lille I, Univ., France DARA, Bonn, Germany CNR, Milano, Italy CNR, Bologna, Italy Nagoya Univ., Japan Graz Univ., Austria Napoli, Universita Napoli, Universita Arizona Univ. Colorado Univ. Bari Univ. Virginia Univ. La Plata Univ. Sydney Univ. California Instit CNRS, Nice, France Laval Univ. Napoli, Univ. Utrecht Univ. Trieste Univ. Leeds Univ. Leicester Univ. Rochester Univ. Shiraz Univ. Leeds Univ. Leicester Univ. Rochester Univ. Shiraz Univ. Radio Astronomy Observatory Catania Univ. Catania, Univ. Catania Univ. Catania, Univ. Chicago Univ. Texas Univ. Muenster Univ. Athens Univ. Jena, Univ. Bonn, Univ. Wisconsin Univ. Barcelona Univ. Paris VI, Univ. Cornell Univ. Toronto Univ. Bologna, Univ. Palermo Univ Palermo Univ. Pisa Univ. Szeged Univ. Oxford Univ. Nanjing Univ. Lund Univ. Columbia Univ. Tokyo Univ. Bologna Univ. Liege Univ. Leiden Univ. Keele Univ. Hirosaki University, Japan Columbia University Alabama, University Pune, University Catania, Universita Arizona, University Giessen, Universitaet Tufts University, Medford, MA Nagoya, University, Japan Fukui University, Japan Oita University, Japan Kyoto University, Japan Nagoya, University, Japan Fukui University, Japan Oita University, Japan Kyoto University, Japan ISO Observatory ISO Observatory Pavia, Universita Santiago Univ., Spain Kyoto Univ., Kyoto, Japan Univ. of Tokyo, Meguro, Tokyo, Japan Yunnan Observatory, Yunnan, China The University of Tokyo, Nagano, Japan New South Wales, University, Sydney, Australia California, University, San Diego, CA Alabama, University, Birmingham Hosei University, Tokyo, Japan ESA, Astronomy Div. Noordwijk, Netherlands Univ. of Michigan, Ann Arbor, MI, US niv. of Michigan, Ann Arbor, MI, US