http://www.economist.com/blogs/gulliver/2012/09/public-transport-costs ---> http://www.bloomberg.com/news/2012-08-26/u-s-taxpayers-are-gouged-on-mass-transit-costs.html и http://www.bloomberg.com/news/2012-08-27/labor-rules-snarl-u-s-commuter-trains.html
А также - http://tunnelbuilder.com/metrosur/edition2pdf/page2.pdf
А также - http://tunnelbuilder.com/metrosur/edition2pdf/page2.pdf