C.P. Maag, J. Roßbach, and J. Zemella,
   "Numerical Studies of the Influence of the Electron Bunch Arrival Time Jitter on the Gain Process of an XFEL-Oscillator for the European XFEL",
   in Proc. 37th International Free Electron Laser Conference, Daejeon, Republic of Korea, August 2015, paper TUP032, pp. 436-438,
    ISBN: 978-3-95450-134-2,
    doi:10.18429/JACoW-FEL2015-TUP032,
    http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/tup032.pdf, 2015.