Burkan, W. C. (1996). Wide-Angle vision: Beat your competition by tocusing on fringe competitors, lost customers, and rogue employees. Wiley.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Burkan, Wayne C. Wide-Angle Vision: Beat Your Competition by Tocusing on Fringe Competitors, Lost Customers, and Rogue Employees. New York: Wiley, 1996.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Burkan, Wayne C. Wide-Angle Vision: Beat Your Competition by Tocusing on Fringe Competitors, Lost Customers, and Rogue Employees. Wiley, 1996.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.