Duckworth, A. (2017). Grit. Penguin Random House, UK.
Lua i Stíl Chicago (17ú heag.)Duckworth, Angela. Grit. London: Penguin Random House, UK, 2017.
Lua MLA (9ú heag.)Duckworth, Angela. Grit. Penguin Random House, UK, 2017.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.