(1991). A Rationale and Set of Principles for the Development of a Systematic Approach to English Diction in Choral Performance Robert E. Fisher. [microform].
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)A Rationale and Set of Principles for the Development of a Systematic Approach to English Diction in Choral Performance Robert E. Fisher. [microform]. 1991.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)A Rationale and Set of Principles for the Development of a Systematic Approach to English Diction in Choral Performance Robert E. Fisher. [microform]. 1991.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.