<https://secure.gravatar.com/avatar/4cee4e27903495871d7ccda25aaf15f8?s=96&amp;d=mm&amp;r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://blog.wwagner.net/allgemein/videos-verkleinern-ohne-qualitaetsverlust/>