Definitions, methodology and other information regarding telecommunication indicators can be found in the ITU's Telecommunication Indicator Handbook. Application of the indicator including country data can be found in the ITU's World Telecommunication Development Report. The data are also provided by the ITU to other agencies and appear in the following publications: UN Statistical Yearbook, World Bank
World Development Indicators, UNDP Human Development Communication Outlook and EUROSTAT Communications Statistics.
Internet site: http://www.itu.int/ict