%\cite{MacArthur:FEL2015-WEP004}
\bibitem{MacArthur:FEL2015-WEP004}
    J.P.~MacArthur, Z.~Huang, A.A.~Lutman, A.~Marinelli, and H.-D.~Nuhn,
   \textquotedblleft{Energy Spread Constraints on Field Suppression in a Reverse Tapered Undulator}\textquotedblright,
%  in \emph{Proc. FEL2015}, WEP004, pp. 597--601,
%  in \emph{Proc. FEL2015}, Daejeon, Republic of Korea, August 2015, paper WEP004, pp. 597--601,
   in \emph{Proc. 37th International Free Electron Laser Conference (FEL2015)}, Daejeon, Republic of Korea, August 2015, paper WEP004, pp. 597--601,
    ISBN: 978-3-95450-134-2,
    \url{http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/wep004.pdf},
    doi:10.18429/JACoW-FEL2015-WEP004, 2015.