1. L.J. Bachman, B.D. Lindsey, J.W. Brakebill, and D.S. Powars . 1998 . Ground-water discharge and base-flow nitrate loads of nontidal streams, and their relation to a hydrogeomorphic classification of the Chesapeake Bay watershed, middle Atlantic coast . USGS Water-Resources Investigations Report 98-4059.
2. E. Busenberg, E.P. Weeks, L.N. Plummer, and R.C. Bartholemay . 1993 . Age dating ground water by use of chlorofluorocarbons (CC13F and CC12F2), and distribution of chlorofluorocarbons in the unsaturated zone, Snake River Plain aquifer, Idaho National Engineering Laboratory, Idaho . USGS Water-Resources Investigations Report93 -4054 .
3. Use of chlorofluorocarbons (CCl3F and CCl2F2) as hydrologic tracers and age-dating tools: The alluvium and terrace system of central Oklahoma
4. Dating young groundwater with sulfur hexafluoride: Natural and anthropogenic sources of sulfur hexafluoride