G.L. Wang, D.X. Dai, G.R. Wu, X.M. Yang, and W.Q. Zhang,
   "Operating of SXFEL in a Single Stage High Gain Harmonic Generation Scheme",
   in Proc. 37th International Free Electron Laser Conference, Daejeon, Republic of Korea, August 2015, paper MOC04, pp. 29-33,
    ISBN: 978-3-95450-134-2,
    doi:10.18429/JACoW-FEL2015-MOC04,
    http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/moc04.pdf, 2015.