Li, Yongkun, and Kaihong Zhao. “2 N Positive Periodic Solutions to N Species non‐autonomous Lotka‐volterra Unidirectional Food Chains With Harvesting Terms”. Mathematical Modelling and Analysis 15, no. 3 (July 15, 2010): 313-326. Accessed November 12, 2024. https://transport.vilniustech.lt/index.php/MMA/article/view/6027.