1. Government of Spain – Aporta Project.
http://administracionelectronica.gob.es
2. Council of Madrid City – Air Quality Integral System.
http://www.mambiente.munimadrid.es/opencms/opencms/calaire/SistemaIntegral/concepto.html
3. Council of Madrid City – Scenarios for the control of emissions during high periods of NO2 concentration in the air.
http://www.mambiente.munimadrid.es/opencms/opencms/calaire/ServCiudadanos/ProtocoloNO2.html
4. European Union – European Commission Environment.
http://ec.europa.eu/environment/air/quality/standards.htm
5. Prada, F.P., Monzon, A.: Identifying Traffic Emissions Hotspots for Urban Air Quality Interventions: The Case of Madrid City (No. 17-05015) (2017)