<https://secure.gravatar.com/avatar/903fbe7609507af7fd9225226be9ea13?s=96&amp;d=mm&amp;r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.alleenpuur.nl/kan-een-houtkachel-nog-wel-langer/>