1. TEC-MME, “7th international workshop on low temperature electronics”, WOLTE-7, 21–23 June 2006, ESTEC
2. http://www.earth.nasa.gov/history/lageos/lageos.html
3. http://www.gfz-potsdam.de/pb1/op/champ/index_CHAMP.html
4. http://www.gfz-potsdam.de/pb1/op/grace/index_GRACE.html
5. http://www.esa.int/esaLP/LPgoce.html