O. OMAR; M. MOHAMED; S. MUHAMMAD. Positive periodic solutions of singular first order difference equations. Applied Mathematics and Computational Intelligence (AMCI), [S. l.], v. 1, n. 1, p. 24–32, 2012. Disponível em: https://ejournal.unimap.edu.my/index.php/amci/article/view/48. Acesso em: 2 may. 2024.