Parthey, C. G., Matveev, A., Alnis, J., Beyer, A., Pohl, R., Predehl, K., Udem, T., Kolachevsky, N., Abgrall, M., Rovera, D., Salomon, C., Laurent, P., & Hänsch, T. W. (2011). Precision spectroscopy on atomic hydrogen. In Proceedings of SPIE.