Planetary Period Oscillations of Saturn's Dayside Equatorial Ionospheric Electron Density Observed on Cassini's Proximal Passes. - Provan, G.; Cowley, S. W. H.; Bunce, E. J.; Milan, S. E.; Persoon, A. M.; Gurnett, D. A. (Journal of Geophysical Research. Space Physics, 2021)