@misc{cryptoeprint:2008:306,
author = {M. B. Paterson and D. R. Stinson and R. Wei},
title = {Combinatorial batch codes},
howpublished = {Cryptology ePrint Archive, Report 2008/306},
year = {2008},
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.