Votes and violence: evidence from a field experiment in Nigeria
This site provides free access to a 56 page report by Paul Collier and Pedro C. Vicente which was published as CSAE working paper 2008-16 by the Centre for the Study of African Economies in 2008. It examines political corruption in the 2007 Nigerian elections, arguing that voter intimidation leads to low voter turnout levels. Intute.ac.uk
http://www.csae.ox.ac.uk/workingpapers/pdfs/2008-16text.pdf