1. Centre for Transportation Studies, 1993. Analysis of travel behaviour in Singapore. Research Report, Nanyang Technological University, Singapore.
2. Hau, T.D., 1992. Economic foundations of road pricing – a diagrammatic analysis. Policy Research Working Paper 1070, The World Bank.
3. Behavioral and resource values of travel time savings: a bicentennial update;Hensher;Australian Road Research,1989
4. Pricing road congestion: recent evidence from Singapore;McCarthy;Policy Studies Journal,1993
5. Menon, A.P.G., Lam, S.H., 1992. Singapore's road pricing system 1975–1989. Research Report 92-2, Centre for Transportation Studies, Nanyang Technological University, Singapore.