TY - JOUR AU - Pan, Lijun TI - Existence of periodic solutions for second order delay differential equations with impulses JO - Electronic Journal of Differential Equations PY - 2011 VL - 2011 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/EJDE_2011__2011__a57/ LA - en ID - EJDE_2011__2011__a57 ER -