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)