Cita APA (7th ed.)

Santayana, G. (1962). The life of reason or the phases of human progress. Collier.

Cita Chicago (17th ed.)

Santayana, George. The Life of Reason or the Phases of Human Progress. Nueva York: Collier, 1962.

Cita MLA (9th ed.)

Santayana, George. The Life of Reason or the Phases of Human Progress. Collier, 1962.