Erschienen in: Proceeding of the 18th ACM conference on Information and knowledge management - CIKM '09. New York, New York, USA: ACM Press, 2009, pp. 1915-1918. ISBN 978-1-60558-512-3. Available under: doi: 10.1145/1645953.1646264
Erschienen in: FORTUNATO, Santo, ed., Giuseppe MANGIONI, ed., Ronaldo MENEZES, ed., Vincenzo NICOSIA, ed.. Complex Networks. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009, pp. 83-97. Studies in Computational Intelligence. 207. ISBN 978-3-642-01205-1. Available under: doi: 10.1007/978-3-642-01206-8_8
