Lapointe, A., Phillips, G. W., & Mead, N. A. (1989). A world of differences: An international assessment of mathematics and science. Educational Testing Service.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Lapointe, Archie, Gary W. Phillips, و Nancy A. Mead. A World of Differences: An International Assessment of Mathematics and Science. [Princeton, N.J.]: Educational Testing Service, 1989.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Lapointe, Archie, et al. A World of Differences: An International Assessment of Mathematics and Science. Educational Testing Service, 1989.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.