Deiss, L. (1979). The essential question. World Library Publications.
Lua i Stíl Chicago (17ú heag.)Deiss, Lucien. The Essential Question. Chicago: World Library Publications, 1979.
Lua MLA (8ú heag.)Deiss, Lucien. The Essential Question. World Library Publications, 1979.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.