„Commissioner's Report“(PDF). Transport for London. 26 March 2014. pp. 3–4. Suarchyvuota(PDF) iš originalo 10 October 2022. Nuoroda tikrinta 2 April 2014.
„Commissioner's Report“(PDF). Transport for London. 26 March 2014. pp. 3–4. Suarchyvuota(PDF) iš originalo 10 October 2022. Nuoroda tikrinta 2 April 2014.
„Annual Report and Statement of Accounts 2011/12“(PDF). Londono transportas. pp. 98, 100. Nuoroda tikrinta 2015-10-25. „Fares revenue on LU was £2,410m... Operating expenditure on the Underground increased to £2,630m“
London Underground. „Standard Tube Map“(PDF). Transport for London. Suarchyvuota(PDF) iš originalo 25 June 2017. Nuoroda tikrinta 1 December 2017.