APA
Al Ries, . (1996). Focus : the future of your company depends on it. HarperBusiness, New York: .
Chicago
Al Ries, . 1996. Focus : the future of your company depends on it. HarperBusiness, New York: .
Harvard
Al Ries, . (1996). Focus : the future of your company depends on it. HarperBusiness, New York: .
MLA
Al Ries, . Focus : the future of your company depends on it. HarperBusiness, New York: . 1996.