<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/54ca69f23c5e4_-_diggers_02_0810-lg-70174608.jpg>
<http://www.popularmechanics.com/science/environment/g211/extreme-digging-machine-pictures/>