The magnetoelectric effects in weak ferromagnetic YMn2O5 modulated structure: a Landau theory approach M. M. Tehranchi and A. Phirouznia Eur. Phys. J. B, 75 4 (2010) 439-442 Published online: 12 May 2010 DOI: 10.1140/epjb/e2010-00143-1