C. Emma, Y. Ding, Z. Huang, A.A. Lutman, G. Marcus, A. Marinelli, and C. Pellegrini,
   "Femtosecond X-ray Pulse Generation with an Energy Chirped Electron Beam",
   in Proc. 37th International Free Electron Laser Conference, Daejeon, Republic of Korea, August 2015, paper WEP075, pp. 722-725,
    ISBN: 978-3-95450-134-2,
    doi:10.18429/JACoW-FEL2015-WEP075,
    http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/wep075.pdf, 2015.