Urban land area (sq. km) - China, Turkmenistan
Center for International Earth Science Information Network ( CIESIN )/Columbia University. 2013. Urban-Rural Population and Land Area Estimates Version 2. Palisades, NY: NASA Socioeconomic Data and Applications Center ( SEDAC ). sedac.ciesin.columbia.edu/data/set/lecz-urban-rural-population-land-area-estimates-v2.