@article{article0db27b29,
title   = {On the efficiency of transportation systems in large cities},
author = {Costa, Luciano da Fontoura and Travençolo, B. A. N. and Viana, M. P. and Strano, E.},
year = {2010},
doi = {10.1209/0295-5075/91/18003},
journal   = {Europhysics Letters}
}