<https://detiru.net/wp-content/uploads/2021/07/\u0434\u0435\u0440\u0435\u0432\u043E6.png>
<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>