Observational Requirements for Long-Term Monitoring of the Global Mean Sea Level and Its Components Over the Altimetry Era - Anny Cazenave; Ben Hamlington; Martin Horwath; Valentina R. Barletta; Jérôme Benveniste; Don Chambers; Petra Döll; Anna E. Hogg; Jean François Legeais; Mark Merrifield; Benoit Meyssignac; Garry Mitchum; et al. (Frontiers in Marine Science, 2019)