Cryptology ePrint Archive: BibTeX Citation of Report 2013/420

@misc{cryptoeprint:2013:420,
    author = {B. Skoric and J.-J. Oosterwijk and J. Doumen},
    title = {The Holey Grail: A special score function for non-binary traitor tracing},
    howpublished = {Cryptology ePrint Archive, Report 2013/420},
    year = {2013},
    note = {\url{http://eprint.iacr.org/}},
}

You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.