1. CIESIN (Consortium for International Earth Science Information Network) (1996), Population density grid of the USA, Columbia University, New York, NY.
2. Burning waste gas in oil fields;Croft;Nature,1973
3. Nighttime images of the earth from space;Croft;Sci. Am.,1978
4. The brightness of lights on Earth at night, digitally recorded by DMSP satellite, Stanford Research Institute Final Report;Croft,1979
5. The 1-km AVHRR global land data set;Eidenshink;Int. J. Remote Sens.,1994