LI, WAN-TONG, and SUI-SUN CHENG. “AN OSCILLATiON THEOREM FOR A NEUTRAL DIFFERENCE EQUATION WITH POSITIVE AND NEGATIVE COEFFICIENTS”. Tamkang Journal of Mathematics 30, no. 1 (March 1, 1999): 39–46. Accessed December 22, 2024. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4204.