TY - JOUR AU - Girg, Petr TI - Existence of periodic solutions for a semilinear ordinary differential equation JO - Electronic Journal of Differential Equations PY - 1998 VL - 1998 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/EJDE_1998__1998__a28/ LA - en ID - EJDE_1998__1998__a28 ER -