TY - JOUR AU - Nieto, Juan J. TI - Periodic solutions for third order ordinary differential equations JO - Commentationes Mathematicae Universitatis Carolinae PY - 1991 SP - 495 EP - 499 VL - 32 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/CMUC_1991__32_3_a10/ LA - en ID - CMUC_1991__32_3_a10 ER -