Cryptology ePrint Archive: BibTeX Citation of Report 2011/061

@misc{cryptoeprint:2011:061,
    author = {Masoumeh Safkhani, Majid Naderi, Nasour Bagheri and Somitra Kumar Sanadhya},
    title = {Cryptanalysis of Some Protocols for RFID Systems},
    howpublished = {Cryptology ePrint Archive, Report 2011/061},
    year = {2011},
    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.