<https://secure.gravatar.com/avatar/eaeb4361964481cf7707d6b4a6518c9d?s=96&amp;d=mm&amp;r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.mugai-ryu.net/seminar-mit-pruefungen-in-dietzenbach-frankfurt/>