kaufman, J. (2013). The first 20 hours: How to learn anything fast. Portfolio Penguin.
Citazione stile Chigago Style (17a edizione)kaufman, Josh. The First 20 Hours: How to Learn Anything Fast. London: Portfolio Penguin, 2013.
Citatione MLA (9a ed.)kaufman, Josh. The First 20 Hours: How to Learn Anything Fast. Portfolio Penguin, 2013.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.