About Leeds. www.bookinghime.com. [1 February 2009]. (原始内容存档于2008年5月9日).
brookings.edu
Istrate, Emilia; Nadeau, Carey Anne. Global MetroMonitor. Washington, DC: The Brookings Institution. November 2012 [23 December 2013]. (原始内容存档于2013年6月4日).
doi.org
Haywood, Russ. Britain's national railway network: fit for purpose in the 21st century?. Journal of Transport Geography (Elsevier). 2007, 15 (3): 198–216. doi:10.1016/j.jtrangeo.2006.02.015.
Istrate, Emilia; Nadeau, Carey Anne. Global MetroMonitor. Washington, DC: The Brookings Institution. November 2012 [23 December 2013]. (原始内容存档于2013年6月4日).