kaufman, J. (2013). The first 20 hours: How to learn anything fast. Portfolio Penguin.
Lua i Stíl Chicago (17ú heag.)kaufman, Josh. The First 20 Hours: How to Learn Anything Fast. London: Portfolio Penguin, 2013.
Lua MLA (9ú heag.)kaufman, Josh. The First 20 Hours: How to Learn Anything Fast. Portfolio Penguin, 2013.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.