G. StupakovP. Emma,
   "Reversible Electron Beam Heater without Transverse Deflecting Cavities",
   in Proc. 37th International Free Electron Laser Conference, Daejeon, Republic of Korea, August 2015, paper MOP056, pp. 166-170,
    ISBN: 978-3-95450-134-2,
    doi:10.18429/JACoW-FEL2015-MOP056,
    http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/mop056.pdf, 2015.