@book{39967,
	author = {Small, Kenneth A. and Verhoef, E. T.},
	title = {The economics of urban transportation},
	publisher = {Routledge},
	year = {2007},
	address = {Nueva York (Estados Unidos)},
	url = {http://www.loc.gov/catdir/toc/ecip0715/2007014080.html}
}