Shape Coexistence Near Neutron Number N=20: First Identification of the E0 Decay from the Deformed First Excited J(pi)=0(+) State in Mg-30 - Schwerdtfeger, W.; Thirolf, P. G.; Wimmer, K.; Habs, D.; Mach, H.; Rodriguez, T. R.; Bildstein, V.; Egido, J. L.; Fraile, L. M.; Gernhaeuser, R.; Hertenberger, R.; Heyde, K.; et al. (Physical Review Letters, 2009)