<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/2012/12/10/121210145644__64629419_c0136474-global_business_conceptual_artwork-spl.jpg>
<http://www.bbc.com/mundo/noticias/2012/12/121210_economia_arbitraje_internacional_rg.shtml>