@article{article87587706,
title   = {Limit sets and the Poincaré-Bendixson theorem in impulsive semidynamical systems},
author = {Bonotto, Everaldo de Mello and Federson, Marcia},
year = {2008},
doi = {10.1016/j.jde.2008.02.007},
journal   = {Journal of Differential Equations}
}