<https://flat-stand.com/event/20201205-1/attachment/ios-%E3%81%AE%E7%94%BB%E5%83%8F-13-4/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://flat-stand.com/event/20201205-1/attachment/ios-%E3%81%AE%E7%94%BB%E5%83%8F-13-4/>