1. Aksnes K, P H Andersen, and E Haugen (1988). A precise multipass method for satellite doppler positioning. Celest. Mech., Vol. 44, pp. 317–388.
2. Andersen P H (1986). GEOSAT — a computer program for precise reduction and simulation of satellite tracking data. In proc. of the Fourth Int. Geod. Symp. on Satellite Geodesy, Austin, Texas, April 28 – May 2.
3. Andersen P H, S Hauge and K Aksnes (1992). ERS-1 orbit determination : Experiments and results. In proc. of the Sixth Int. Geod. Symp. on Satellite Positioning, Columbus, Ohio, March 17 – 20.
4. Andersen P H and S Hauge (1992). GPS orbit determination and relative positioning using data from the GIG'91 campaign. In proc. of the Sixth Int. Geod. Symp. on Satellite Positioning, Columbus, Ohio, March 17 – 20.
5. Beutler G, W Gurtner, I Bauersima, and R Langley (1985). Modelling and estimating the orbits of GPS satellites, Proc. of the 1st Int. Symp. on Precise Positioning with the Global Positioning System, U. S. Dept. of Commerce, Rockville, Md.