Watkins, C. (2002). Marketing, sales and customer services: Understanding the theory and practice of selling through service. Institute of Financial Services ; A.I.T.B.S. Publishers & Distributors.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Watkins, Charley. Marketing, Sales and Customer Services: Understanding the Theory and Practice of Selling Through Service. Canterbury : New Delhi: Institute of Financial Services ; A.I.T.B.S. Publishers & Distributors, 2002.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Watkins, Charley. Marketing, Sales and Customer Services: Understanding the Theory and Practice of Selling Through Service. Institute of Financial Services ; A.I.T.B.S. Publishers & Distributors, 2002.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.