%\cite{Ding:FEL2015-TUA01}
\bibitem{Ding:FEL2015-TUA01}
    Y.~Ding,
   \textquotedblleft{Generating Femtosecond to Sub-Femtosecond X-Ray Pulses at Free-Electron Lasers}\textquotedblright,
%  presented at FEL2015, Daejeon, Republic of Korea, August 2015, paper TUA01, unpublished.
   presented at the 37th International Free Electron Laser Conference (FEL2015), Daejeon, Republic of Korea, August 2015, paper TUA01, unpublished.