GB CODES FOR THE ADMINISTRATIVE DIVISIONS OF THE PEOPLE'S REPUBLIC OF CHINA (http://sedac.ciesin.org/china/admin/gbcode/gbcodedata.html) (2010-04-16 04:00:00 UTC).
GB 2260 1991 " the Guobiao Codes of the People's Republic of China. Digitized by CHGIS" (2010-04-14 04:00:00 UTC).