@article{Sobolevsky2013,
author = {Sobolevsky, S. and Szell, M. and Campari, R. and Couronné, T. and Smoreda, Z. and Ratti, C.},
title= {Delineating geographical regions with networks of human interactions in an extensive set of countries},
year = {2013},
volume = {8},
number = {12},
pages = {e81707},
}