@misc{cryptoeprint:2004:268,
    author = {Zhengjun Cao and Lihua Liu},
    title = {Untraceability of Wang-Fu Group Signature Scheme},
    howpublished = {Cryptology ePrint Archive, Report 2004/268},
    year = {2004},
    url = {http://eprint.iacr.org/2004/268},
}