Ondřejov Observatory, Czechoslovakia
J. Kleczek
Sonnenborgh Observatory, Utrecht
R. H. van Gent & Robert J. Rutten
Technical University, Delft
J. C. de Munck
Radio-Observatory, Dwingeloo
C. Slottje
Astrophysical Institute of the Free University, Brussels
G. Severne
Collège de France, Paris
Jean-Claude Pecker
Netherlands Institute for Sea Research, The Netherlands
H. Postma
Sternberg Astronomical Institute, Moscow
L. P. Grishchuk
Observatory Sonnenborgh, Utrecht
H. Niewenhuijzen
Institute of Geological Sciences, Utrecht
R. D. Schuiling
Laboratory for Space Research, Utrecht
H. F. van Beek & Johan Bleeker
Faculty of Law, University of Utrecht, Utrecht, The Netherlands
G. C. M. Reijnen
Observatoire de Paris, Meudon
Jean Heidmann
Institute for Space Aeronomy, Brussels
J. Lemaire
Sterrewacht, Leiden
V. Icke
Tel Aviv University, Tel Aviv, Israel
Y. Neéman
South African Astronomical Observatory, Cape, South Africa
M. W. Feast
Houten, The Netherlands
W. de Graaff