Gartside, L. (1976). Modern business correspondence : a practical: Course for use in schools, and by all who would write better business letters. The English language book society.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Gartside, L. Modern Business Correspondence : A Practical: Course for Use in Schools, and by All Who Would Write Better Business Letters. London: The English language book society, 1976.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Gartside, L. Modern Business Correspondence : A Practical: Course for Use in Schools, and by All Who Would Write Better Business Letters. The English language book society, 1976.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.