1. Angel, S., Parent, J., Civco, D. L. & Blei, A. M. (2018) The shape compactness of urban extents, Working paper WP18SA1, Lincoln Institute of Land Policy. https://www.lincolninst.edu/sites/default/files/pubfiles/angel_wp18sa1.pdf
2. Dovey, K. & Pafka, E. (2016, May 20) Urban density matters – But what does it mean?. The Conservation. http://theconversation.com/urban-density-matters-but-what-does-it-mean-58977