Line shapes of the magnesium resonance lines in cool DZ white dwarf atmospheres N. F. Allard, J. F. Kielkopf, S. Blouin, P. Dufour, F. X. Gadéa, T. Leininger and G. Guillon A&A, 619 (2018) A152 Published online: 19 November 2018 DOI: 10.1051/0004-6361/201834067