Investigation of quasi-realistic heterotic string models with reduced Higgs spectrum G. Cleaver, A. Faraggi, J. Greenwald, D. Moore, K. Pechan, E. Remkus and T. Renner Eur. Phys. J. C, 71 12 (2011) 1842 Published online: 15 December 2011 DOI: 10.1140/epjc/s10052-011-1842-8