Tài liệu tham khảo WikiPedia: Hạt_Harju http://pub.stat.ee/px-web.2001/Dialog/varval.asp?m... http://www.stat.ee/49512 //tools.wmflabs.org/geohack/geohack.php?language=v... https://web.archive.org/web/20110429220724/http://...