G. Geloni, V. Kocharyan, and E. Saldin,
   "Theoretical Computation of the Polarization Characteristics of an X-Ray Free-Electron Laser with Planar Undulator",
   in Proc. 37th International Free Electron Laser Conference, Daejeon, Republic of Korea, August 2015, paper MOP008, pp. 38-42,
    ISBN: 978-3-95450-134-2,
    doi:10.18429/JACoW-FEL2015-MOP008,
    http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/mop008.pdf, 2015.