The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
%\cite{Kim:FEL2017-WEC04} \bibitem{Kim:FEL2017-WEC04} D.E. Kim, H.-S. Kang, I.S. Ko, and K.-H. Park, \textquotedblleft{Progress of PAL-XFEL Undulator Program}\textquotedblright, presented at FEL2017, Santa Fe, NM, USA, Aug. 2017, paper WEC04, unpublished. % presented at the 38th Int. Free Electron Laser Conf. (FEL'17), Santa Fe, NM, USA, Aug. 2017, paper WEC04, unpublished.