@book{United Nations2007,
author = {United Nations, Department of Economic and Social Affairs, Population Division, },
title= {World Population Prospects. The 2006 Revision, Vol. I, Comprehensive Tables},
year = {2007},
URL = {http://www.un.org/esa/population/publications/wpp2006/wpp2006.htm},
series = {United Nations publication, Sales No. E.07.XIII.2},
}