<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/54ca8cbabccca_-_rainwater-collect-4s-0709-99713028.jpg>
<http://www.popularmechanics.com/home/how-to/a4353/4322898/>