<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef.bbci.co.uk/news/ws/560/amz/worldservice/live/assets/images/2013/01/03/130103020804_tapeworms_304x171_spl.jpg>
<http://www.bbc.com/mundo/noticias/2013/01/130102_curiosidades_dietas_historicas_raras_irm.shtml>