Fiber-laser-based clockwork for long-term measurements and comparisons of visible optical frequency standardsJ. E. Bernard, P. Dubé, A. A. Madej, S. Cundy, J.-S. Boulanger, J. Jiang and D. J. JonesEur. Phys. J. D, 57 2 (2010) 247-252DOI: https://doi.org/10.1140/epjd/e2010-00052-5