<https://congnghe3s.net/nam-mo-thay-qua-na-danh-con-gi-y-nghia-mo-thay-qua-na>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://congnghe3s.net/nam-mo-thay-qua-na-danh-con-gi-y-nghia-mo-thay-qua-na>