1. Bruns H., 1878. Die Figur der Erde. Publ. des Königlichen Preussischen Geodätischen Inst., Berlin, Germany (in German).
2. Gooding R.H., Wagner C.A., Klokočník J., Kostelecký J. and Gruber C., 2007. CHAMP and GRACE resonances, and the gravity field of the Earth. Adv. Space Res., 39, 1604–1611, doi: 10.1016/j.asr.2007.02.086.
3. Harwood N.M., Swinerd G.G. and King-Hele D.G., 1994. Individual Geopotential Harmonic Coefficients of Order 15 from 30 Resonant Satellite Orbit Analysis. Proc. R. Soc. London, Ser. A, 444, 129–147.
4. Heiskanen W.A. and Moritz H., 1967. Physical Geodesy. Freeman and Co., San Francisco.
5. Ihde J. and Sacher M. (Eds), 2002. European Vertical Reference Network, Final Documentation. EUREF Publication No. 11/I, Mittailungen des Bundesamt für Kartografie und Geodäsie, Band 25, Verlag des BKG, Frankfurt/Main (http://www.euref.eu/documentation/ EUVN/vol%20I.pdf).