Absorption spectra of Na atoms in dense HeNicole F. Allard, Akira Nakayama, Fernand Spiegelman, John F. Kielkopf and Frank StienkemeierEur. Phys. J. D, 67 3 (2013) 52DOI: https://doi.org/10.1140/epjd/e2013-30523-x