CHENG, S. S.; XIE, S.-L.; ZHANG, B. G. QUALITATIVE THEORY OF PARTIAL DIFFERENCE EQUATIONS (V): STURMIAN THEOREMS FOR A CLASS OF PARTIAL DIFFERENCE EQUATIONS. Tamkang Journal of Mathematics, [S. l.], v. 27, n. 1, p. 89–97, 1996. DOI: 10.5556/j.tkjm.27.1996.4366. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4366. Acesso em: 25 apr. 2024.