Grauwin, Sebastian
Szell, Michael
Sobolevsky, Stanislav
Hövel, Philipp
Simini, Filippo
Vanhoof, Maarten
Smoreda, Zbigniew
Barabási, Albert-László
Ratti, Carlo
Article History
Received: 31 August 2016
Accepted: 27 March 2017
First Online: 26 April 2017
Competing interests
: The authors declare no competing financial interests.