Title: Proceedings of open meetings of working groups of the sixteenth plenary meeting of COSPAR, Constance, F.R.G., 23 May-5 June 1973 and resumés of the Symposium on Noctilucent Clouds and Intrplanetary Dust, Constance, F.R.G., 24 and 25 May 1973
Subjects: Astronautics in astronomy, Astronautics in geophysics, Astronautics in meteorology, Congresses