APA

Ries Al,, . (2005). Focus : the future of your company depends on it. New York: Collins Business Essentials.

Chicago

Ries Al,, . 2005. Focus : the future of your company depends on it. New York: Collins Business Essentials.

Harvard

Ries Al,, . (2005). Focus : the future of your company depends on it. New York: Collins Business Essentials.

MLA

Ries Al,, . Focus : the future of your company depends on it. New York: Collins Business Essentials. 2005.