中国科学院数学与系统科学研究院期刊网
AMS
The Subvariety Lattice of the Join of Two Semigroup Varieties
Wen Ting ZHANG, Yan Feng LUO
Acta Mathematica Sinica . 2009, (6): 971 -982 .  DOI: 10.1007/s10114-009-7281-x