<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/480x360/54cb1e4db0877_-_concrete-fasteners-05a-1013-de.jpg>
<http://www.popularmechanics.com/home/tools/reviews/g1314/how-to-fasten-anything-to-concrete/>