%\cite{Kim:FEL2015-WEB03}
\bibitem{Kim:FEL2015-WEB03}
    K.-J.~Kim, J.~Arthur, Y.~Ding, W.M.~Fawley, J.C.~Frisch, J.B.~Hastings, \emph{et al.},
%   K.-J. Kim \emph{et al.},
   \textquotedblleft{Progress Towards an X-ray FEL Oscillator}\textquotedblright,
%  presented at FEL2015, Daejeon, Republic of Korea, August 2015, paper WEB03, unpublished.
   presented at the 37th International Free Electron Laser Conference (FEL2015), Daejeon, Republic of Korea, August 2015, paper WEB03, unpublished.