1. Abbaspour M, Soltaninejad A (2004) Design of an environmental assessment model on the effect of vehicle emissions in greater Tehran on air pollution with economic sensitivity. Int J Environ Sci Technol 1:27–38
2. American Public Transportation Association (2008) Public transportation reduces greenhouse gases and conserves energy: the benefits of public transportation. http://www.apta.com/resources/reportsandpublications/Documents/greenhouse_brochure.pdf
3. Asche F et al (2012) Gas versus oil prices the impact of shale gas. Energy Policy 44:117–124
4. Barton H (1992) City transport: strategies for sustainability. In: Breheny MJ (ed) Sustainable development and urban form, European research in regional science 2. Pion, London, pp 197–216
5. BP (2012) BP statistical review of world energy, June 2012. BP p.l.c. http://www.bp.com/assets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2011/STAGING/local_assets/pdf/statistical_review_of_world_energy_full_report_2012.pdf