Cita APA (7th ed.)

Ingram, G. K., & Liu, Z. (1998). Vehicles, roads, and road use: Alternative empirical specifications. World Bank.

Cita Chicago (17th ed.)

Ingram, Gregory K., i Zhi Liu. Vehicles, Roads, and Road Use: Alternative Empirical Specifications. Washington, D.C: World Bank, 1998.

Cita MLA (9th ed.)

Ingram, Gregory K., i Zhi Liu. Vehicles, Roads, and Road Use: Alternative Empirical Specifications. World Bank, 1998.