Cita APA (7th ed.)
Santayana, G. (1947). The middle span. Constable.
Cita Chicago (17th ed.)
Santayana, George. The Middle Span. London: Constable, 1947.
Cita MLA (9th ed.)
Santayana, George. The Middle Span. Constable, 1947.
Atenció: Aquestes cites poden no estar 100% correctes.