The Wikipedia articles on Academic fencing, the Studentenverbindungen (~fraternities) who practise it, and duelling scars are all worth reading. So are their German counterparts, which have lots of pictures. (Click on 'Deutsch' in the left-hand column, under languages, to get there.)
Mark Twain: At the Students' Dueling Ground, Dueling by Wholesale, from A Tramp Abroad, 1870s.
Jerome K. Jerome: an account of academic fencing from Three Men on the Bummel, 1914.
An historical perspective on mensur fencing.
An account of academic fencing in a modern German fraternity. Another one. (Both comments on MetaFilter.)
'Men of Iron' by J. Christoph Amberger, an essay on the difference between fencing and duelling.