@article{Rietveld1999,
author = {Rietveld, P. and Zwart, B. and van Wee, B. and van den Hoorn, T.},
title= {On the relationship between travel time and travel distance of commuters},
year = {1999},
doi = {10.1007/s001680050105},
volume = {33},
number = {3},
pages = {269--287},
}