Ries, A. (1996). Focus: The future of your company depends on it. New York: HarperBusiness.
Styl cytowania ChicagoRies, Al. Focus: The Future of Your Company Depends On It. New York: HarperBusiness, 1996.
Styl cytowania MLARies, Al. Focus: The Future of Your Company Depends On It. New York: HarperBusiness, 1996.
Uwaga: Te cytaty mogą odróżniać się od wytycznej twojego fakultetu..