Scharpf, Fritz W. "Legitimacy in the Multi-level European Polity." The Twilight of Constitutionalism?. : Oxford University Press, 2010-02-11. Oxford Scholarship Online. 2010-05-01. Date Accessed 25 May. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199585007.001.0001/acprof-9780199585007-chapter-5>.
Scharpf, F.(2010-02-11). Legitimacy in the Multi-level European Polity. In The Twilight of Constitutionalism?. : Oxford University Press. Retrieved 25 May. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199585007.001.0001/acprof-9780199585007-chapter-5.
Scharpf, Fritz W. "Legitimacy in the Multi-level European Polity." In The Twilight of Constitutionalism?. : Oxford University Press, 2010-02-11. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199585007.001.0001/acprof-9780199585007-chapter-5.
Scharpf FW. Legitimacy in the Multi-level European Polity. In: Dobner P, Loughlin M. The Twilight of Constitutionalism?. Oxford University Press; 2010. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199585007.001.0001/acprof-9780199585007-chapter-5. Accessed May 25, 2013.