Crespo López-Urrutia, J. R. Division Prof. Dr. Thomas Pfeifer, MPI for Nuclear Physics, Max Planck Society;
https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.90.045005 (Publisher version)
Kozlov, M., Safronova, M., Crespo López-Urrutia, J. R., & Schmidt, P. (2018). Highly charged ions: Optical clocks and applications in fundamental physics. Reviews of Modern Physics, 90: 045005. doi:10.1103/RevModPhys.90.045005.