%\cite{van der Slot:FEL2015-TUP003}
\bibitem{van der Slot:FEL2015-TUP003}
    P.J.M.~van der Slot, K.-J.~Boller, and A.~Strooisma,
   \textquotedblleft{Threshold of a Mirror-less Photonic Free Electron Laser Oscillator Pumped by One or More Electron Beams}\textquotedblright,
%  in \emph{Proc. FEL2015}, TUP003, pp. 327--330,
%  in \emph{Proc. FEL2015}, Daejeon, Republic of Korea, August 2015, paper TUP003, pp. 327--330,
   in \emph{Proc. 37th International Free Electron Laser Conference (FEL2015)}, Daejeon, Republic of Korea, August 2015, paper TUP003, pp. 327--330,
    ISBN: 978-3-95450-134-2,
    \url{http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/tup003.pdf},
    doi:10.18429/JACoW-FEL2015-TUP003, 2015.
