E. SchneidmillerM.V. Yurkov,
   "Optimization of a High Efficiency Free Electron Laser Amplifier",
   in Proc. 37th International Free Electron Laser Conference, Daejeon, Republic of Korea, August 2015, paper MOC02, pp. 17-23,
    ISBN: 978-3-95450-134-2,
    doi:10.18429/JACoW-FEL2015-MOC02,
    http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/moc02.pdf, 2015.