<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/2012/11/20/121120113008_vietnam_bank_304x171_reuters.jpg>
<http://bbcvietnamese.com/vietnamese/vietnam/2013/04/130412_vn_social_stratification.shtml>