<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef-1.bbci.co.uk/news/560/media/images/72628000/jpg/_72628058_t3950309-nanoindenter_for_hardness_testing-spl.jpg>
<http://www.bbc.com/news/science-environment-25961243>