<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/06/320x480/54cfd021169cc_-_solar-system-04-0112-de.jpg>
<http://www.popularmechanics.com/space/deep-space/g744/5-weird-planetary-systems/>