Chen, J. H., Edwards, R. L., and Wasserburg, G. J., 1986. 238-U, 234-U and 232-Th in seawater. Earth Planet. Sci. Lett. 80: 241-251.

Palmer, M. R., and Edmond, J. M., 1993.  Uranium in river water.  Geochim. Cosmochim. Acta 57: 4947-4955.