1. The World Bank Group: data.worldbank.org.
2. Borja J. Counterpoint: Intelligent cities and innovative cities. Universitat Oberta de Catalunya. E-Journal on the Knowledge Society 5, 2007.
3. Toppeta D. The Smart City Vision: How Innovation and ICT Can Build Smart, “Livable”, Sustainable Cities. The Innovation Knowledge Foundation, 2010.
4. Washburn D, Sindhu U, Balaouras S, Dines RA, Hayes NM, Nelson LE. Helping CIOs Understand “Smart City” Initiatives: Defining the Smart City, Its Drivers, and the Role of the CIO. Cambridge MA, Forrester Research, Inc. 2010.
5. Albino V, Berardi U, Dangelico RM. Smart Cities: Definitions, Dimensions, Performance, and Initiatives. Journal of Urban Technology, 2015.