SHEN, J. H.; WANG, Z. C.; QIAN, X. Z. ON EXISTENCE OF POSITIVE SOLUTIONS OF NEUTRAL DIFFERENCE EQUATIONS. Tamkang Journal of Mathematics, [S. l.], v. 25, n. 3, p. 257–265, 1994. DOI: 10.5556/j.tkjm.25.1994.4453. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4453. Acesso em: 7 may. 2024.