M. Burchfield, H. Overman, D. Puga, and M. Turner, Causes of sprawl: a portrait from space [online], 2006.

R. Ihaka and R. Gentleman, The R project for statistical computing [Online; accessed 18, 1993.

Y. Rubner, C. Tomasi, and L. J. Guibas, The earth mover's distance as a metric for image retrieval, International Journal of Computer Vision, vol.40, issue.2, pp.99-121, 2000.
DOI : 10.1023/A:1026543900054

G. Sherman, Quantum geographic information system, 2002.

J. Michael, D. H. Swain, and . Ballard, Color indexing, International Journal of Computer Vision, vol.7, pp.11-32, 1991.

F. Warmerdam, Geospatial data abstraction library [Online ; accessed 18, 1993.
DOI : 10.1007/978-3-540-74831-1_5

. Wikipedia, Urban sprawl. URL http://en.wikipedia.org/wiki/Urban_sprawl. [Online; accessed 21, 2013.

L. Wilkinson and M. Friendly, The History of the Cluster Heat Map, The American Statistician, vol.63, issue.2, pp.179-184, 2009.
DOI : 10.1198/tas.2009.0033