1. B. D. Tapley, S. Bettadpur, M. M. Watkins, and Ch. Reigber, Geophys. Res. Lett. 31, L09607 (2004).
2. R. P. Kornfeld, B. W. Arnold, M. A. Gross, N. T. Dahya, W. M. Klipstein, P. F. Gath, and S. Bettadpur, J. Spacecr. Rockets 56, 931 (2019).
3. T. Reubelt, N. Sneeuw and M. A. Sharifi, in Gravity, Geoid and Earth Observation, Ed. by S. P. Mertikas (Springer, 2010), p. 163.
4. A. S. Zhamkov and V. K. Milyukov, Izvestiya, Physics of the Solid Earth 57, 266 (2021).
5. P. L. Bender, D. Wiese, and R. S. Nerem, in Proceedings of the 3rd International Symposium on Formation Flying, Missions and Technologies, ESA/ESTEC, Noordwijk, April 23–25, 2008, The Netherlands (2008), p. 1.