Tài liệu tham khảo WikiPedia: Cư_Yên //tools.wmflabs.org/geohack/geohack.php?language=v... http://www.gso.gov.vn/phuong-phap-thong-ke/danh-mu... https://www.google.com/books/edition/%C4%90%E1%BB%... https://thuvienphapluat.vn/van-ban/bo-may-hanh-chi...
