Cita APA (7th ed.)

Polley, R. L. (1965). Herbert Hoover's: Challenge to America. His life and words (1a. ed.). Country Beautiful Foundation.

Cita Chicago (17th ed.)

Polley, Robert L. Herbert Hoover's: Challenge to America. His Life and Words. 1a. ed. Nueva York: Country Beautiful Foundation, 1965.

Cita MLA (9th ed.)

Polley, Robert L. Herbert Hoover's: Challenge to America. His Life and Words. 1a. ed. Country Beautiful Foundation, 1965.