<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef-1.bbci.co.uk/news/560/media/images/57436000/jpg/_57436209_r2500133-coloured_pictorial_plaque_on_pioneer_10_and_11-spl.jpg>
<http://www.bbc.com/news/science-environment-16273512>