[1]
Sánchez, L. 1994. A Note on Nontrivial Peniodic Solutions of Dynamical Systems with Subquadratic Potential. Revista Matemática Complutense. 7, 1 (Jan. 1994), 179. DOI:https://doi.org/10.5209/rev_REMA.1994.v7.n1.17799.