TY - JOUR TI - Quadratic systems with invariant straight lines of total multiplicity two having Darboux invariants PY - 2015 AU - Llibre, Jaume AU - Oliveira, Regilene Delazari dos Santos T2 - Communications in Contemporary Mathematics SN - 0219-1997 DO - 10.1142/S0219199714500187 UR - https://doi.org/10.1142/S0219199714500187 PP - Singapore VL - 17 IS - 3 SP - 1450018-1-1450018-17 ER -