Williamson, T., & Trust, A. (1987). On knowledge of the unknowable. Blackwell Publishing.
Lua i Stíl Chicago (17ú heag.)Williamson, T., agus Analysis Trust. On Knowledge of the Unknowable. Blackwell Publishing, 1987.
Lua MLA (9ú heag.)Williamson, T., agus Analysis Trust. On Knowledge of the Unknowable. Blackwell Publishing, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.