Wulf, L. d., & Sokol, J. B. (2005). Customs modernization handbook. World Bank.
Cita Chicago (17th ed.)Wulf, Luc de, i José B. Sokol. Customs Modernization Handbook. Washington, DC: World Bank, 2005.
Cita MLA (9th ed.)Wulf, Luc de, i José B. Sokol. Customs Modernization Handbook. World Bank, 2005.
Atenció: Aquestes cites poden no estar 100% correctes.