<https://secure.gravatar.com/avatar/c180c7b6af6700793e2e5dcbcc11e480?s=96&amp;d=mm&amp;r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://detiru.net/how-to-draw-a-tree-easy-step-by-step-tutorial.html>