- Wen Ting Zhang, Yan Feng Luo, “The subvariety lattice of the join of two semigroup varieties”, Acta. Math. Sin.-English Ser., 25, № 6, 2009, 971
- Edmond W. H. Lee, “Finite Basis Problem for Semigroups of Order Five or Less: Generalization and Revisitation”, Stud Logica, 101, № 1, 2013, 95
- L. N. Shevrin, B. M. Vernikov, M. V. Volkov, “Lattices of semigroup varieties”, Russ Math., 53, № 3, 2009, 1
- Peter R. Jones, “On lattices of varieties of restriction semigroups”, Semigroup Forum, 86, № 2, 2013, 337
- Wen Ting Zhang, Yan Feng Luo, “On Varieties Generated by Minimal Complex Semigroups”, Order, 25, № 3, 2008, 243
- M. V. Volkov, S. V. Goldberg, S. I. Kublanovsky, “A minimal nonfinitely based semigroup whose variety is polynomially recognizable”, J Math Sci, 177, № 6, 2011, 847
- Edmond W. H. Lee, Wen Ting Zhang, “Finite basis problem for semigroups of order six”, LMS J. Comput. Math., 18, № 1, 2015, 1
- Edmond W. H. Lee, “Hereditarily finitely based monoids of extensive transformations”, Algebra Univers., 61, № 1, 2009, 31
- Edmond Lee, “Varieties generated by 2-testable monoids”, Studia Scientiarum Mathematicarum Hungarica, 49, № 3, 2012, 366
- PETER R. JONES, “THE SEMIGROUPS B2 AND B0 ARE INHERENTLY NONFINITELY BASED, AS RESTRICTION SEMIGROUPS”, Int. J. Algebra Comput., 23, № 06, 2013, 1289