Preker, A. S., & Langenbrunner, J. (2004). Spending wisely: Buying health services for the poor. World Bank.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Preker, Alexander S., و Jack Langenbrunner. Spending Wisely: Buying Health Services for the Poor. Washington, DC: World Bank, 2004.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Preker, Alexander S., و Jack Langenbrunner. Spending Wisely: Buying Health Services for the Poor. World Bank, 2004.