GNSS Observations of Earth Orientation Jim Ray, NOAA/NGS 1. Polar motion observability using GNSS – concepts, complications, & error sources – subdaily. - ppt download
Polar motion - Wikipedia
Movements in the Earth's interior are the missing link of polar motion: GFZ
Analysis and prediction of polar motion using MSSA method | Earth, Planets and Space | Full Text
What drives 20th century polar motion? - ScienceDirect
Polar Motion: The Causes of Spin Axis Drift - Profolus
Fundamentals of Satellite Navigation
The polar motion of the Earth. | Download Scientific Diagram
Why is Earth's spin axis drifting? | Earth | EarthSky
Analysis of Earth's polar motion and length of day trends in comparison with estimates using second degree stokes coefficients from satellite gravimetry - ScienceDirect
Climate Change is Shifting Earth's Axis of Rotation-ForumIAS Blog