1. Dziewonski, A.M. and Anderson, D.L., Preliminary Reference Earth Model, Earth Planet. Inter., 1981, vol. 25, pp. 297–356.
2. Gilbert, F. and Dziewonski, A.M., An Application of Normal Mode Theory to the Retrieval of Structural Parameters and Source Mechanisms from Seismic Spectra, Philos. Trans. R. Soc., A, 1975, vol. 278, no. 1280, pp. 187–269.
3. Masters, T.G. and Gilbert, F., Attenuation in the Earth at Low Frequencies, Philos. Trans. R. Soc., A, 1983, vol. A308, pp. 479–522.
4. Masters, T.G. and Widmer, R., Free Oscillations: Frequencies and Attenuations, in Global Earth Physics: A Handbook of Physical Constants, Ahrens, Th., Ed., Washington, DC: AGU, 1995, pp. 104–125.
5. Molodenskii, S.M. and Molodenskaya, M.S., On Mechanical Q Parameters of the Lower Mantle Inferred from Data on the Earth’s Free Oscillations and Nutation, Izv. Phys. Solid Earth, 2009, vol. 45, no. 9, pp. 766–752.