Birdsall, S. S., & Florin, J. (1992). Outline of american geography: Regional landscapes of the united states (Fourth edition.). John Wiley.
Lua i Stíl Chicago (17ú heag.)Birdsall, Stephen S., agus John Florin. Outline of American Geography: Regional Landscapes of the United States. Fourth edition. New York: John Wiley, 1992.
Lua MLA (9ú heag.)Birdsall, Stephen S., agus John Florin. Outline of American Geography: Regional Landscapes of the United States. Fourth edition. John Wiley, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.