Mikhailova, J. M., Fedorov, M. V., Karpowicz, N., Gibbon, P., Platonenko, V. T., Zheltikov, A. M., & Krausz, F. (2012). Isolated Attosecond Pulses from Laser-Driven Synchrotron Radiation. Physical Review Letters, 109(24):. doi:10.1103/PhysRevLett.109.245005.