National Service Center for Environmental Publications NSCEP / U.S. Environmental Protection Agency EPA. Onsite Wastewater Treatment Systems Manual.
Chicago-referens (17:e uppl.)National Service Center for Environmental Publications NSCEP / U.S. Environmental Protection Agency EPA. Onsite Wastewater Treatment Systems Manual.
MLA-referens (9:e uppl.)National Service Center for Environmental Publications NSCEP / U.S. Environmental Protection Agency EPA. Onsite Wastewater Treatment Systems Manual.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.