1. Department of Transport. Transport Statistics: Great Britain 1974–1984. HMSO (1985)
2. T. Bendixson. Transport in the Nineties: The Shaping of Europe. RICS (1989)
3. Institution of Civil Engineers, Infrastructure Policy Group (IPG). Congestion. ICE (1989)
4. Confederation of British Industry. Transport in London, Task Force Report: The Capital at Risk (1989)
5. J.C. Yu. Transportation Engineering. Elsevier (1982)