Ferguson, J. H., & McHenry, D. E. (1970). Elements of American Government (9th ed.). McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Ferguson, John Henry, agus Dean Eugene McHenry. Elements of American Government. 9th ed. New York: McGraw-Hill, 1970.
Lua MLA (9ú heag.)Ferguson, John Henry, agus Dean Eugene McHenry. Elements of American Government. 9th ed. McGraw-Hill, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.