High-precision masses of 29-33Mg and the N = 20 shell “closure” D. Lunney, G. Audi, C. Gaulard, M. de Saint Simon, C. Thibault and N. Vieira Eur. Phys. J. A, 28 1 (2006) 129-138 Published online: 19 June 2006 DOI: 10.1140/epja/i2005-10281-1