Ries, A. (1996). Focus: The future of your company depends on it. New York: HarperBusiness.
Stile di citazione ChicagoRies, Al. Focus: The Future of Your Company Depends On It. New York: HarperBusiness, 1996.
Citazione MLARies, Al. Focus: The Future of Your Company Depends On It. New York: HarperBusiness, 1996.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.