<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef.bbci.co.uk/news/ws/560/amz/worldservice/live/assets/images/2014/04/24/140424154142_visa_passport_304x171_thinkstock_nocredit.jpg>
<http://www.bbc.com/mundo/noticias/2014/05/140423_america_latina_pasaportes_visas_jp.shtml>