中国科学院数学与系统科学研究院期刊网
EXISTENCE OF MANYPERIODIC SOLUTIONS TO THE TWO-DIMENSIONAL DIFFERENTIAL DIFFERENCE EQUATIONS
Dong Da WANG, Ji Fang SUN, Jing Qing SHEN
Acta Mathematicae Applicatae Sinica . 2003, (1): 40 -46 .  DOI: 10.12387/C2003004