Hehlen, M. P., Greco, R. R., Rellergert, W. G., Sullivan, S. T., DeMille, D., Jackson, R. A., …Torgerson, J. R. (2013). Optical spectroscopy of an atomic nucleus: Progress toward direct observation of the 229Th isomer transition. Journal of Luminescence, 133, 91-95. https://doi.org/10.1016/j.jlumin.2011.09.037