Geach, P. T. (1977). The virtues. Cambridge University Press.
Lua i Stíl Chicago (17ú heag.)Geach, P. T. The Virtues. Cambridge: Cambridge University Press, 1977.
Lua MLA (8ú heag.)Geach, P. T. The Virtues. Cambridge University Press, 1977.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.