<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef.bbci.co.uk/news/ws/560/amz/worldservice/live/assets/images/2014/07/02/140702021611_sp_african_cichlid_464x261_pa.jpg>
<http://www.bbc.com/mundo/ultimas_noticias/2014/07/140701_ultnot_memoria_de_los_peces_bd.shtml>