<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://cos.h-cdn.co/assets/cm/14/28/53bebf4b2214b_-_cos-0312-jump-rope-mdn.jpg>
<http://www.cosmopolitan.com/health-fitness/news/a10163/jump-rope-workout/>