Please consider referencing the following conference paper in addition to the journal paper.

@inproceedings{blac-ccs07,
  author = {Patrick P. Tsang and  Man Ho Au and Apu Kapadia and Sean W. Smith},
  title = "{Blacklistable Anonymous Credentials: Blocking Misbehaving Users without {TTPs}}",
  booktitle = {Proceedings of the 14th ACM Conference on Computer and Communications Security ({CCS})},
  pages = {72--81},
  doi = {10.1145/1315245.1315256},
  month = oct # "/" # nov,
  year = {2007}
}

@article{blac-tissec,
 author = {Tsang, Patrick P. and Au, Man Ho and Kapadia, Apu and Smith, Sean W.},
 title = {{BLAC}: Revoking Repeatedly Misbehaving Anonymous Users without Relying on {TTPs}},
 journal = {ACM Transactions on Information and System Security},
 issue_date = {December 2010},
 volume = {13},
 issue = {4},
 month = {December},
 year = {2010},
 issn = {1094-9224},
 pages = {39:1--39:33},
 articleno = {39},
 numpages = {33},
 url = {http://doi.acm.org/10.1145/1880022.1880033},
 doi = {http://doi.acm.org/10.1145/1880022.1880033},
 acmid = {1880033},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {Privacy, anonymous authentication, anonymous blacklisting, privacy-enhanced revocation, user misbehavior},
}