<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/480x360/54cb303142b41_-_bho-submarines-08-0414-lgn.jpg>
<http://www.popularmechanics.com/military/navy-ships/g1464/a-brief-history-of-the-submarine/>