Analysis of information sources in references of the Wikipedia article "List of metropolitan areas in Europe" in English language version.
Until recently, there was no harmonised definition of 'a city' for European and other countries member of the Organisation for Economic Cooperation and Development (OECD). This undermined the comparability, and thus also the credibility, of cross-country analysis of cities. To resolve this problem, the OECD and the European Commission developed a new definition of a city and its commuting zone in 2011. […] Each city is part of its own commuting zone or a polycentric commuting zone covering multiple cities. These commuting zones are significant, especially for larger cities. The cities and commuting zones together (called Larger Urban Zones) account for 60 % of the EU population.
Within the Urban Audit, (...) functional urban areas were previously referred to as 'larger urban zones'.
