Wu, X. ., Watkins, M. M., Ivins, E. R., Kwok, R. ., Wang, P. ., & Wahr, J. M. (2002). Toward global inverse solutions for current and past ice mass variations: Contribution of secular satellite gravity and topography change measurements. Journal of Geophysical Research (Solid Earth), 107, 2291. http://doi.org/10.1029/2001JB000543 (Original work published November 2002)