<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/480x360/54cb0021dd28a_-_historic-guns-11-1112-de.jpg>
<http://www.popularmechanics.com/military/weapons/g1002/the-11-most-important-guns-in-history/>