<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/54cb337b7101e_-_tractor-beam-mdn.jpg>
<http://www.popularmechanics.com/space/a10510/a-tractor-beam-made-of-sound-16754329/>