On 6th July 2010 I made a presentation for the course “Einführung in das Information Retrieval” at Universität Bielefeld named “A language modeling framework for expert finding” based on the paper with the same name written by Krisztian Balog, Leif Azzopardi and Maarten de Rijke from the University of Amsterdam.
Here it is a link to the original paper: http://staff.science.uva.nl/~kbalog/files/ipm2008-esearch.pdf
Here they are the slides I used during the presentation: Slides