CHENG SS, XIE S-L, ZHANG BG. QUALITATIVE THEORY OF PARTIAL DIFFERENCE EQUATIONS (V): STURMIAN THEOREMS FOR A CLASS OF PARTIAL DIFFERENCE EQUATIONS. Tamkang J. Math. [Internet]. 1996 Mar. 1 [cited 2024 Apr. 25];27(1):89-97. Available from: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4366