Oepts, D., van der Meer, A. F. G., Bakker, R. J., & van Amersfoort, P. W. (1993). Selection of Single-Mode Radiation from a Short-Pulse Free-Electron Laser. Physical Review Letters, 70, 3255-3258. https://doi.org/10.1103/PhysRevLett.70.3255 (Original work published 1993)
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