<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef.bbci.co.uk/news/ws/560/amz/worldservice/live/assets/images/2012/12/28/121228103425_espacio_2.jpg>
<http://www.bbc.com/mundo/video_fotos/2013/01/121228_galeria_en_fotos_2012_desde_el_espacio_jbo.shtml>