<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/54ca8cba3fac6_-_rainwater-collect-3s-0709-91478721.jpg>
<http://www.popularmechanics.com/home/how-to/a4353/4322898/>