National Center for Education Statistics. (1999). Education statistics quarterly. National Center for Education Statistics, Office of Educational Research and Improvement, U.S. Dept. of Education.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)National Center for Education Statistics. Education Statistics Quarterly. Washington, DC: National Center for Education Statistics, Office of Educational Research and Improvement, U.S. Dept. of Education, 1999.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)National Center for Education Statistics. Education Statistics Quarterly. National Center for Education Statistics, Office of Educational Research and Improvement, U.S. Dept. of Education, 1999.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.