<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/480x240/54cb1e4c3d9e4_-_concrete-fasteners-01-1013-lgn.jpg>
<http://www.popularmechanics.com/home/tools/reviews/g1314/how-to-fasten-anything-to-concrete/>