Atomic energy levels : as derived from the analyses of optical spectra-the spectra of Hydrogen, Deuterium, Tritium, Helium, Lithium, Berlyllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Sodium, Magnesium, Aluminium, Silicon, Phosphorus, Sulfur, Chlorine, Argon, Potassium, Calcium, Scandium, Titanium, and Vanadaium / vol. 1. - Moore, Charlotte E. (Circular of the National Bureau of Standards ;, 1949)