Karshenboim, Savely G. Laser Spectroscopy, Max Planck Institute of Quantum Optics, Max Planck Society;
Angstmann, E. J., Flambaum, V. V., & Karshenboim, S. G. (2004). Cosmological variation of the fine-structure constant versus a new interaction. Physical Review A, 70(4): 044104. doi:10.1103/PhysRevA.70.044104.