<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef-1.bbci.co.uk/news/560/media/images/63161000/jpg/_63161981_b2200405-tem_of_whooping_cough_bacterium-spl.jpg>
<http://www.bbc.com/news/health-19751209>