A few days ago the new world atlas of artificial night sky brightness, by Falchi et al., has been published.
The article is a substantial update of the first atlas, published back in 2001 by Cinzano, Falchi, and Elvidge, which allowed for the first time to appreciate the issue of light pollution on a worldwide scale.
In addition to making update maps available, the new publication provide various statistics by country and reports some important statements concerning issues related to LED lighting.
The article is available at: http://advances.sciencemag.org/content/2/6/e1600377.full
The BuioMetria Partecipativa project provided a contribution to the publication, with some data collected by Francesco Giubbilini which was used to calibrate parts of the model used for the creation of the atlas.