United States. Superintendent of Documents. (1994). Environmental protection. U.S. G.P.O., Supt. of Docs.
Chicago-referens (17:e uppl.)United States. Superintendent of Documents. Environmental Protection. Washington, DC: U.S. G.P.O., Supt. of Docs, 1994.
MLA-referens (9:e uppl.)United States. Superintendent of Documents. Environmental Protection. U.S. G.P.O., Supt. of Docs, 1994.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.