1. The Statistical, Economic and Social Research and Training Centre for Islamic Countries (SESRTCIC)
www.sesrtcic.org/statistics/bycountry.php
2. UNESCO Statistics Division
http://stats.uis.unesco.org/ReportFolders/reportfolders.aspx
3. World Development Indicators (WDI), 2006
http://devdata.worldbank.org/wdi2006/contents/index2.htm
4. National Science Board. Science and Engineering Indicators 2006. (National Science Foundation, Arlington, VA)
www.nsf.gov/statistics/seind06/
5. Giles, J. Nature 442, 334 (2006).