United States. Environmental Protection Agency. 8-hour ground-level ozone designations. U.S. Environmental Protection Agency.
Chicago Style (17th ed.) CitationUnited States. Environmental Protection Agency. 8-hour Ground-level Ozone Designations. Washington, D.C.: U.S. Environmental Protection Agency.
MLA (9th ed.) CitationUnited States. Environmental Protection Agency. 8-hour Ground-level Ozone Designations. U.S. Environmental Protection Agency.
Warning: These citations may not always be 100% accurate.