Gackle, M. L. (1987). The effect of selected vocal techniques for breath management, resonation, and vowel unification on tone production in the junior high school female voice.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Gackle, Martha Lynne. The Effect of Selected Vocal Techniques for Breath Management, Resonation, and Vowel Unification on Tone Production in the Junior High School Female Voice. 1987.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Gackle, Martha Lynne. The Effect of Selected Vocal Techniques for Breath Management, Resonation, and Vowel Unification on Tone Production in the Junior High School Female Voice. 1987.
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