Tài liệu tham khảo WikiPedia: Tuyên_Hóa,_Trương_Gia_Khẩu http://en.chinabroadcast.cn/1954/2004-7-16/123@132... http://www.zjkxuanhua.gov.cn/ http://www.cbw.com/business/invest/zhangjiakou/xua... http://www.meet-greatwall.org/english/gwcn/egwcn25... //tools.wmflabs.org/geohack/geohack.php?language=v... https://web.archive.org/web/20041122224902/http://... https://web.archive.org/web/20050310065845/http://...
