You seem to be attempting to access an item that has been removed from the repository.
The item you are trying to access was a duplicate of:
Effing, R.C. and Hillegersberg, J. van and Huibers, T.W.C. (2011) Social media and political participation: are Facebook, Twitter and YouTube democratizing our political systems? In: Third IFIP WG 8.5 International Conference on Electronic Participation, ePart 2011, 29 August - 1 September 2011, Delft, the Netherlands (pp. pp. 25-35).