The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
%\cite{Su:IPAC2017-MOPAB075} \bibitem{Su:IPAC2017-MOPAB075} X.L. Su, Y.-C. Du, W.-H. Huang, Y.F. Liang, L. Niu, C.-X. Tang, \emph{et al.}, % X.L. Su, Y.-C. Du, W.-H. Huang, Y.F. Liang, L. Niu, C.-X. Tang, Q.L. Tian, D. Wang, and L.X. Yan, % X.L. Su \emph{et al.}, \textquotedblleft{Measurement of Electron Bunch Length via a Tunable-Gap Undulator}\textquotedblright, % in \emph{Proc. IPAC2017}, pp. 295--297, % in \emph{Proc. IPAC2017}, Copenhagen, Denmark, May 2017, paper MOPAB075, pp. 295--297, in \emph{Proc. 8th Int. Particle Accelerator Conf. (IPAC'17)}, Copenhagen, Denmark, May 2017, paper MOPAB075, pp. 295--297, % ISBN: 978-3-95450-182-3, \url{http://jacow.org/ipac2017/papers/mopab075.pdf}, \url{https://doi.org/10.18429/JACoW-IPAC2017-MOPAB075}, 2017.