Determining the global minimum of Higgs potentials via Groebner bases – applied to the NMSSM M. Maniatis, A. von Manteuffel and O. Nachtmann Eur. Phys. J. C, 49 4 (2007) 1067-1076 Published online: 20 January 2007 DOI: 10.1140/epjc/s10052-006-0186-2