1. The De-orbiting of GEOS 2;Beech;ESA Bulletin,1984
2. The Geostationary Ring. Physical Properties and Collision Probability;Roth,1984
3. Debris in the Geostationary Ring, The Endless Shooting Gallery;Suddeth,1985
4. The Scientific and Technical Aspects of the Geostationary Orbit;Perek,1987