Summerfield, G. (1968). Voices: The third book. Penguin Education.
Lua i Stíl Chicago (17ú heag.)Summerfield, Goeffrey. Voices: The Third Book. Harmondsworth: Penguin Education, 1968.
Lua MLA (9ú heag.)Summerfield, Goeffrey. Voices: The Third Book. Penguin Education, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.