1. Electronic Road-Pricing Pilot Scheme;Hong Kong Government,1985
2. A Fair Way to Go;Hong Kong Government,1985
3. Road User Changes in Central America;Churchill;World Bank Staff Occasional Paper No. 15,1972
4. Patterns of Urban and Rural Population Growth;United Nations,1980
5. The Economics of Road User Changes;Walters;World Bank Staff Occasional Paper No. 5,1968