BibTex format
@article{Graham:2003:10.1016/S1366-5545(03)00017-6,
author = {Graham, DJ and Couto, A and Adeney, WE and Glaister, S},
doi = {10.1016/S1366-5545(03)00017-6},
journal = {TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW},
pages = {443--458},
title = {Economies of scale and density in urban rail transport: effects on productivity},
url = {http://dx.doi.org/10.1016/S1366-5545(03)00017-6},
volume = {39},
year = {2003}
}