<https://in.element14.com/rubycon/400bxw180mefr18x40/cap-180-f-400v-20/dp/2480360>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://in.element14.com/rubycon/400bxw180mefr18x40/cap-180-f-400v-20/dp/2480360>