<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef.bbci.co.uk/news/560/media/images/58931000/jpg/_58931893_p2340041-coloured_tem_of_section_through_bone_marrow_cells-spl.jpg>
<http://www.bbc.co.uk/news/health-17291310>