참고문헌
- Martin G. Richards(2005), Congestion Charging in London 1p, Palgrave.(단행본)
- 유소영(2014), 도시철도 승객 혼잡완화를 위한 탄력적 요금제도 도입 분석, 철도학회 논문
- London Assembly(2009), Too close for comfort-Passenger's experiences of the London Underground 12p-25p(보고서)
- 구글 인터넷 검색 http://www.nyunews.com/2013/10/24/subway-4/ http://www.pressrun.net/weblog/2013/06/singapore-mrt-more-passengers- than-expected-from-day-one.html http://www.theonlinecitizen.com/2013/03/free-mrt-transportation-solution-congestion/
- Graham Currie, Exploring The Impact of the 'Free Before 7' Campaign on Reducing Overcrowding on Melbournes Trains (논문)