Duffy, A. (1936). The poetry of duty. National Council of Catholic Men.
Lua i Stíl Chicago (17ú heag.)Duffy, Alfred. The Poetry of Duty. Washington, D.C.: National Council of Catholic Men, 1936.
Lua MLA (8ú heag.)Duffy, Alfred. The Poetry of Duty. National Council of Catholic Men, 1936.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.