Rodell, M. ., Chen, J. ., Kato, H. ., Famiglietti, J. ., Nigro, J. ., & Wilson, C. . (2007). Estimating groundwater storage changes in the Mississippi River basin (USA) using GRACE. Hydrogeology Journal, 15, 159–166. http://doi.org/10.1007/s10040-006-0103-7 (Original work published February 2007)