Sternwarte University of Bonn, Bonn, Germany
Klaas S. de Boer
Laboratory for Space Research, SRON, Utrecht
A. C. Brinkman
Mt Stromlo and Siding Spring Observatories, The Australian National University, Canberra
M. A. Dopita
Free University, Amsterdam
J. W. Hovenier
Laboratory for Space Research, Utrecht, The Netherlands
Cornelis de Jager
Polytechnic School at São Paulo, São Paulo University, São Paulo, Brazil
P. Kaufmann
Astronomical Institute, Ondřejov, Czechoslovakia
J. Kleczek
Netherlands Agency for Aerospace Programs (NIVR), Delft
P. F. J. Linssen
Observatory at Ondřejov, Ondřejov, Czechoslovakia
B. Valníček
Kapteyn Astronomical Institute, Groningen
P. C. van der Kruit