Ellis, W. (1972). The knife edge. Macmillan.
Lua i Stíl Chicago (17ú heag.)Ellis, William. The Knife Edge. London: Macmillan, 1972.
Lua MLA (8ú heag.)Ellis, William. The Knife Edge. Macmillan, 1972.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.