<https://rangefinderforum.com/threads/just-got-the-c-biogon-35mm-f2-8.93878/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://rangefinderforum.com/threads/just-got-the-c-biogon-35mm-f2-8.93878/page-22>