Preker, A. S., Scheffler, R. M., & Bassett, M. C. (2007). Private voluntary health insurance in development: Friend or foe. World Bank.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Preker, Alexander S., Richard M. Scheffler, و Mark C. Bassett. Private Voluntary Health Insurance in Development: Friend or Foe. Washington, D.C.: World Bank, 2007.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Preker, Alexander S., et al. Private Voluntary Health Insurance in Development: Friend or Foe. World Bank, 2007.