Ries, A. (1996). Focus: The future of your company depends on it. New York: HarperBusiness.
シカゴスタイル引用形Ries, Al. Focus: The Future of Your Company Depends On It. New York: HarperBusiness, 1996.
MLA引用形式Ries, Al. Focus: The Future of Your Company Depends On It. New York: HarperBusiness, 1996.
警告: この引用は必ずしも正確ではありません.