1. Agenzia Nazionale per la Sicurezza del Volo (ANSV). (2004) Milano Linate Ground Collision, Reference A/1/04, 20 January.
2. Bundesstelle für Flugunfalluntersuchung (BFU). (2004) Accident on 1 July 2002 near Überlingen, Report AX001-1-2/02.
3. Devine, J. and Smith, A. (2007) Safety Culture Enhancement Activities and Next Steps within the Federal Aviation Administration, Proceedings of International Systems Safety Society; August, Baltimore, MD. Unionville VA: ISSC (ISBN 0-9721385-7-9).
4. European Commission. (2004a) Regulation No. 549/2004 of the European Parliament and of the Council of 10 March 2004 Laying Down the Framework for the Creation of the Single European Sky, Official Journal of the European Union.
5. European Commission. (2004b) Regulation No. 551/2004 of the European Parliament and of the Council of 10 March 2004 on the Organisation and Use of the Airspace in the Single European Sky, Official Journal of the European Union.