@article{10_4064_sm215_3_1,
     author = {Ver\'onica Poblete and Juan C. Pozo},
     title = {Periodic solutions of an abstract
 third-order differential equation},
     journal = {Studia Mathematica},
     pages = {195--219},
     year = {2013},
     volume = {215},
     number = {3},
     doi = {10.4064/sm215-3-1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm215-3-1/}
}