Cryptology ePrint Archive: BibTeX Citation of Report 2007/311

@misc{cryptoeprint:2007:311,
    author = {Jean-Luc Beuchat and Masaaki Shirase and Tsuyoshi Takagi and Eiji Okamoto},
    title = {A Refined Algorithm for the $\eta_T$ Pairing Calculation in Characteristic Three},
    howpublished = {Cryptology ePrint Archive, Report 2007/311},
    year = {2007},
    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.