Williams, T. (2010). Positioning for professionals: How professional knowledge firms can differentiate their way to success. Wiley.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Williams, Tim. Positioning for Professionals: How Professional Knowledge Firms Can Differentiate Their Way to Success. Hoboken, N.J.: Wiley, 2010.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Williams, Tim. Positioning for Professionals: How Professional Knowledge Firms Can Differentiate Their Way to Success. Wiley, 2010.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.