Tài liệu tham khảo WikiPedia: Kẻ_Sặt //tools.wmflabs.org/geohack/geohack.php?language=v... http://www.gso.gov.vn/phuong-phap-thong-ke/danh-mu... http://thitrankesat.binhgiang.haiduong.gov.vn/Arti... https://thuvienphapluat.vn/van-ban/Bo-may-hanh-chi...