WU, S.-T.; TSAI, L.-Y. Periodic solutions for dynamic equations on time scales. Tamkang Journal of Mathematics, [S. l.], v. 40, n. 2, p. 173–191, 2009. DOI: 10.5556/j.tkjm.40.2009.466. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/466. Acesso em: 6 may. 2024.