<http://danketoan.com/threads/de-duoc-hoan-thue-thu-nhap-ca-nhan-thi-phai-chuan-bi-nhung-gi.282455/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://danketoan.com/threads/de-duoc-hoan-thue-thu-nhap-ca-nhan-thi-phai-chuan-bi-nhung-gi.282455/#post-1266615>