1. Biking and Walking: The Position of Non-Motorized Transport Modes in Transport Systems,;Rietveld;Tinbergen Institute Discussion Papers 01-111/3,2001
2. Issues in sustainable transportation international,;Litman;Journal of Global Environment Issues.,2006
3. World Commission on Environment and Development.1987.Our Common Future. Brundtland Report. Oxford University Press, Oxford.
4. North American transportation: perspectives on research needs and sustainable transportation;Black;Journal of Transport Geography,1997
5. Transport and climate change: a review;Chapman;Journal of Transport Geography,2007