1. Abreu S (2005) La corrupción. Published in monografías.com.
http://www.monografias.com/trabajos24/corrupcion/corrupcion.shtml
2. Benito B, Guillamón MD, Bastida F (2015) Determinants of urban political corruption in local governments. Crime Law Soc Change 63(3):191–210
3. Council of the European Union (2003) Framework Decision 2003/568/JHA of 22 July 2003 on combating corruption in the private sector. Available at
http://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32003F0568
4. PricewaterhouseCoopers and Ecorys (2013) Identifying and reducing corruption in public procurement in the EU – development of a methodology to estimate the direct costs of corruption and other elements for an EU-evaluation mechanism in the area of anti-corruption. Available at
https://ec.europa.eu/anti-fraud/sites/antifraud/files/docs/body/identifying_reducing_corruption_in_public_procurement_en.pdf
5. European Parliament (2003) Report on the communication from the commission to the council, the European parliament and the European economic and social committee – on a comprehensive EU policy against corruption (COM(2003) 317 – 2003/2154(INI)). Available at
http://blog.transparency.org/wp-content/uploads/2011/06/2003-EP-Rutelli-report-on-a-comprehensive-AC-policy.pdf