Cryptology ePrint Archive: BibTeX Citation of Report 2013/199

@misc{cryptoeprint:2013:199,
    author = {Daniel J. Bernstein and Stacey Jeffery and Tanja Lange and Alexander Meurer},
    title = {Quantum algorithms for the subset-sum problem},
    howpublished = {Cryptology ePrint Archive, Report 2013/199},
    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.