A workshop dedicated to earth rotation problems was held in Bonas, France, June 11–13, 1985. It was organized by the North Atlantic Treaty Organization (NATO) Scientific Affairs Division and the Council of Europe and was attended by 39 participants from eight different countries.
In the last 10 years, extremely precise measurements of the earth's rotation parameters and new global geophysical data have become available, allowing major advances to be made in the understanding of the various irregularities affecting the earth's rotation. The aim of this workshop was to bring together scientists who have made important contributions in this field during the last decade, both at the observational and geophysical interpretation levels. The first session was dedicated to the definition, implementation, and maintenance of the terrestrial and celestial reference systems.