1. 40 CFR § 435.50. Applicability; description of the beneficial use subcategory
2. 70 Federal Register 2262, Wednesday, 12 January 2005
3. Adriano DC (2001) Trace elements in terrestrial environments: biogeochemistry, bioavailability, and risks of metals, 2nd edn. Springer, New York
4. Agency for Toxic Substances and Disease Registry [ATSDR] (1995) Toxicological profile for polycyclic aromatic hydrocarbons. U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, Division of Toxicology and Environmental Medicine/Applied Toxicology Branch, Atlanta. http://www.atsdr.cdc.gov/toxprofiles/tp69.pdf . Accessed 4 Mar 2014
5. Agency for Toxic Substances and Disease Registry [ATSDR] (1999) Toxicological profile for n-hexane. U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, Division of Toxicology and Environmental Medicine/Applied Toxicology Branch, Atlanta. http://www.atsdr.cdc.gov/toxprofiles/tp113.pdf . Accessed 13 Apr 2010