<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/2014/04/16/140416154433_centennial_light_304x171_bbc.jpg>
<http://www.bbc.com/mundo/noticias/2014/04/140416_respuestas_curiosos_17abril_finde_aa.shtml>