Cita APA (7th ed.)

Cather, W. (1989). O pioneers¡ (1a. ed.). Bantam Books.

Cita Chicago (17th ed.)

Cather, Willa. O Pioneers¡. 1a. ed. Toronto: Bantam Books, 1989.

Cita MLA (9th ed.)

Cather, Willa. O Pioneers¡. 1a. ed. Bantam Books, 1989.