Cita APA (7a ed.)

Cather, W., & Gelfant, B. H. (1994). O pioneers! Penguin Books.

Cita Chicago Style (17a ed.)

Cather, Willa, y Blanche H. Gelfant. O Pioneers! New York [etc.]: Penguin Books, 1994.

Cita MLA (9a ed.)

Cather, Willa, y Blanche H. Gelfant. O Pioneers! Penguin Books, 1994.