Ingram, G. K., & Liu, Z. (1998). Vehicles, roads, and road use: Alternative empirical specifications. World Bank.
芝加哥风格引文Ingram, Gregory K., 与 Zhi Liu. Vehicles, Roads, and Road Use: Alternative Empirical Specifications. Washington, D.C: World Bank, 1998.
MLA引文Ingram, Gregory K., 与 Zhi Liu. Vehicles, Roads, and Road Use: Alternative Empirical Specifications. World Bank, 1998.
警告：这些引文格式不一定是100％准确.