中国科学院数学与系统科学研究院期刊网
Four Positive Periodic Solutions for a Discrete Lotka-Volterra Cooperative System with Harvesting Terms
LIAO Huaying, ZHOU Zheng
Acta Mathematicae Applicatae Sinica . 2016, (3): 441 -451 .  DOI: 10.12387/C2016040