<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/06/480x480/54cfd665b9ad9_-_trainsafety-01-0414-de.jpg>
<http://www.popularmechanics.com/technology/infrastructure/g1484/4-ways-to-make-our-trains-safer-16701886/>