中国科学院数学与系统科学研究院期刊网
Semigroup 5-Graded Ring and Smash Product R#S~*
Zi Long ZHANG, Bing Ling CAI,
Acta Mathematica Sinica, Chinese Series . 2004, (5): 985 -992 .  DOI: 10.12386/A2004sxxb0123