Covey, S. R. (2012). The 3rd alternative: Solving life's most difficult problems. Simon & Schuster UK.
Citazione stile Chigago Style (17a edizione)Covey, Stephen R. The 3rd Alternative: Solving Life's Most Difficult Problems. London: Simon & Schuster UK, 2012.
Citatione MLA (9a ed.)Covey, Stephen R. The 3rd Alternative: Solving Life's Most Difficult Problems. Simon & Schuster UK, 2012.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.