%\cite{Sei:FEL2015-MOP050}
\bibitem{Sei:FEL2015-MOP050}
    N.~Sei, K.~Hayakawa, Y.~Hayakawa, M.~Inagaki, K.~Nakao, K.~Nogami, \emph{et al.},
%   N. Sei \emph{et al.},
   \textquotedblleft{Development of Coherent Terahertz Wave Sources using  LEBRA and KU-FEL S-band Linacs}\textquotedblright,
%  in \emph{Proc. FEL2015}, MOP050, pp. 143--146,
%  in \emph{Proc. FEL2015}, Daejeon, Republic of Korea, August 2015, paper MOP050, pp. 143--146,
   in \emph{Proc. 37th International Free Electron Laser Conference (FEL2015)}, Daejeon, Republic of Korea, August 2015, paper MOP050, pp. 143--146,
    ISBN: 978-3-95450-134-2,
    \url{http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/mop050.pdf},
    doi:10.18429/JACoW-FEL2015-MOP050, 2015.