Cita APA (7a ed.)

Summerfield, G. (1968). Voices: The third book. Penguin Education.

Cita Chicago Style (17a ed.)

Summerfield, Goeffrey. Voices: The Third Book. Harmondsworth: Penguin Education, 1968.

Cita MLA (9a ed.)

Summerfield, Goeffrey. Voices: The Third Book. Penguin Education, 1968.