This bibliography from the Toxic Substances Hydrology Program at the US Geological Survey (USGS) "contains citations of reports on research conducted under the auspices of the Program since the beginning of the Program." References to papers, reports, abstracts, and fact sheets can be found for field investigations of contaminated sites, methods development, investigations of contamination from non-point sources, and more. Hyperlinks to abstracts and publications located online make this an especially useful resource. Continuously updated, the bibliography has recently become even more useful with the addition of a search feature.