Z. Tibai, G. Almási, Zs. Csiha-Nagy, J.A. Fülöp, J. Hebling, and Gy. Tóth,
   "Carrier-Envelope-Phase Stable Linearly and Circularly Polarized Attosecond Pulse Sources",
   in Proc. 37th International Free Electron Laser Conference, Daejeon, Republic of Korea, August 2015, paper MOP071, pp. 205-208,
    ISBN: 978-3-95450-134-2,
    doi:10.18429/JACoW-FEL2015-MOP071,
    http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/mop071.pdf, 2015.