References and Notes for Actinium ( Ac )

BW92b J. Blaise and J.-F. Wyart, Energy Levels and Atomic Spectra of Actinides, International Tables of Selected Constants 20, Paris (1992). Also available at http//www.lac.u.psud.fr/Database/Contents.html.
MFT57 W. F. Meggers, M. Fred, F. S. Tomkins, J. Res. Natl. Bur. Stand. (U.S.) 58, 297 (1957). The data pertain to the 227Ac isotope. The designations for several of the odd-parity levels of Ac II are taken from [BW92b].
MHRS74 W. C. Martin, L. Hagan, J. Reader, and J. Sugar, J. Phys. Chem. Ref. Data 3, 771 (1974).
S74 J. Sugar, J. Chem. Phys. 60, 4103 (1974).