Cita APA (7a ed.)

Field, M., & Smith, P. (1939). Secrets of nature. The Scientific Book Club.

Cita Chicago Style (17a ed.)

Field, Mary, y Percy Smith. Secrets of Nature. London: The Scientific Book Club, 1939.

Cita MLA (9a ed.)

Field, Mary, y Percy Smith. Secrets of Nature. The Scientific Book Club, 1939.