<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef.bbci.co.uk/news/560/media/images/70111000/jpg/_70111439_c0043604-clostridium_difficile_bacteria,_sem-spl.jpg>
<http://www.bbc.com/news/health-24240409>