1. ABI Research Institute. (2011). Smart cities: Municipal networking, communications, traffic/transportation, and energy.
2. Afonso, O., Monteiro, S., Thompson, M. (2010). A growth model for the Quadruple-helix innovation theory. NIP WP 12/2010.
3. Albino, V., Berardi, U., & Dangelico, R. M. (2015). Smart cities: Definitions, dimensions, performance, and initiatives. Journal of Urban Technology, 22(1), 3–21.
4. Alcatel, L. (2012). Getting smart about smart cities. Alcatel Lucent Market Analysis.
5. Arnkil, R., Järvensivu, A., Koski, P., Piitainen, T. (2010). Exploring Quadruple-helix: Outlining user-oriented innovation models (Working Papers 85/2010). University of Tampere.