Smiles, S. (1881). Duty: With illustrations of courage, patience and endurance. Harper & Brothers.
Lua i Stíl Chicago (17ú heag.)Smiles, Samuel. Duty: With Illustrations of Courage, Patience and Endurance. New York: Harper & Brothers, 1881.
Lua MLA (8ú heag.)Smiles, Samuel. Duty: With Illustrations of Courage, Patience and Endurance. Harper & Brothers, 1881.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.