1. Methods of Celestial Mechanics;Beutler,2004
2. Combining consecutive short arcs into long arcs for precise and efficient GPS orbit determination;Beutler;Journal of Geodesy,1996
3. Flury, W., Massart, A., Schildknecht, T., Hugentobler, U., Kuusela, J., Sodnik, Z. Searching for small debris in the geostationary ring – discoveries with the Zeiss 1-metre telescope. ESA Bulletin No. 104, pp. 92 ff, November 2000.
4. Hugentobler, U., Schaer, S., Fridez, P. Bernese GPS Software Version 4.2. Druckerei der Universität Bern, Switzerland, 2001.
5. Schildknecht, T. The search for space debris in high-altitude orbits. Habilitation Thesis, Druckerei der Universität Bern, Switzerland, 2003.