<https://www.todoereaders.com/calibre-incorpora-un-editor-de-ebooks.html>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.todoereaders.com/fi/kaliiperi-sis%C3%A4lt%C3%A4%C3%A4-e-kirjaeditorin.html>