World Bank Group. (1999). Natural gas: Private sector participation and market development. World Bank Group.
Chicago-viite (17. p.)World Bank Group. Natural Gas: Private Sector Participation and Market Development. Washington, D.C: World Bank Group, 1999.
MLA-viite (9. p.)World Bank Group. Natural Gas: Private Sector Participation and Market Development. World Bank Group, 1999.
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