Birdsall, S. S. (1992). Outline of American geography: Regional landscapes of the united States (4th ed.). John Willey.
Citazione stile Chigago Style (17a edizione)Birdsall, Stephen S. Outline of American Geography: Regional Landscapes of the United States. 4th ed. California: John Willey, 1992.
Citatione MLA (9a ed.)Birdsall, Stephen S. Outline of American Geography: Regional Landscapes of the United States. 4th ed. John Willey, 1992.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.