<https://zh.coursera.org/learn/moqaddima-fi-al-tasweeq-aabr-wasael-al-tawasol-al-ijtimai#mooc>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://zh.coursera.org/learn/moqaddima-fi-al-tasweeq-aabr-wasael-al-tawasol-al-ijtimai>