Gale Research Inc. (1987). Class L. Education: Library of Congress classification schedules combined with additions and changes through . Gale Research Inc..
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Gale Research Inc. Class L. Education: Library of Congress Classification Schedules Combined with Additions and Changes Through . Detroit: Gale Research Inc., 1987.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Gale Research Inc. Class L. Education: Library of Congress Classification Schedules Combined with Additions and Changes Through . Gale Research Inc., 1987.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.