<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ghk.h-cdn.co/assets/cm/15/12/640x360/5508ebc678d4f-ghk-0613-calcium-cow-s2.jpg>
<http://www.goodhousekeeping.com/health/diet-nutrition/a13963/calcium-supplements/?src=shelter_footer>