<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/320x426/54cb3030c3896_-_bho-submarines-06-0414-de.jpg>
<http://www.popularmechanics.com/military/navy-ships/g1464/a-brief-history-of-the-submarine/>