1. H.-D. Amberger, H. Reddmann, T.J. Mueller, W.J. Evans, Organometallics, in press. doi:10.1021/om901007f.
2. Spectra and Energy Levels of Rare Earth Ions in Crystals;Dieke,1968
3. Spectroscopic properties of triply ionized lanthanides in transparent host materials;Morrison,1982
4. Rationalization of crystal field parameterization;Görller-Walrand,1996
5. Spectroscopic Properties of Rare Earths in Optical Materials;Liu,2005