<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/06/54cfd8ae81c46_-_rosetta-comet-01-0814-de.jpg>
<http://www.popularmechanics.com/space/deep-space/a11020/3-surprising-comet-facts-weve-already-learned-from-rosetta-17066196/>