Organisation for Economic Co-operation and Development. (1990). OECD economic surveys: Belgium - Luxembourg. Organisation for Economic Co-operation and Development.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Organisation for Economic Co-operation and Development. OECD Economic Surveys: Belgium - Luxembourg. Paris, France: Organisation for Economic Co-operation and Development, 1990.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Organisation for Economic Co-operation and Development. OECD Economic Surveys: Belgium - Luxembourg. Organisation for Economic Co-operation and Development, 1990.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.