Date of Original Version
© ACM, 2008. This is the authors’ version of the work. It is posted here by permission of the ACM for your personal use. Not for redistribution. The definitive version was published in: JCDL’08, June 16–20, 2008, Pittsburgh, Pennsylvania, USA. http://doi.acm.org/10.1145/1378889.1378929
Proceedings of the 8th ACM/IEEE-CS Joint Conference on Digital Libraries. JCDL '08. , 241-250.