Gale Research Company & Dresser, P. D. (1989). New research centers: The supplement to the 13th edition of research centers directory. Gale Research Company.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Gale Research Company و Peter D. Dresser. New Research Centers: The Supplement to the 13th Edition of Research Centers Directory. Detroit: Gale Research Company, 1989.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Gale Research Company و Peter D. Dresser. New Research Centers: The Supplement to the 13th Edition of Research Centers Directory. Gale Research Company, 1989.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.