1. Selected tables from Atomic energy levels as derived from analyses of optical spectra, v. 3, References to rare-earth spectra, ionization potentials: H to La, Hf to Ac, chemical symbols, periodic system [with bibliography]; by Charlotte E. Moore. Bookmark Corporate/Agency Authors: National Bureau of Standards and Commerce Dept. Publisher: National Bureau of Standards Date: [1958.] SuDoc number: C 13.4/a:At 7/2