@misc{cryptoeprint:2004:229,
author = {Xin L¨¹ and Zhi Ma and Dengguo Feng},
title = {Secure Direct Communication Using Quantum Calderbank-Shor-Steane Codes},
howpublished = {Cryptology ePrint Archive, Report 2004/229},
year = {2004},
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.