<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef-1.bbci.co.uk/news/ws/560/amz/worldservice/live/assets/images/2013/05/10/130510104153_heavy_metal_304x171__nocredit.jpg>
<http://www.bbc.com/mundo/noticias/2013/05/130514_universidad_heavy_metal_men.shtml>