- Shi-Yao He, Jian-Cai Wei, Li-Hong Xie, “Complete Invariant ⋆-Metrics on Semigroups and Groups”, Axioms, 11, № 10, 2022,
546 
- Alexander V. Osipov, Konstantin Kazachenko, “Joint continuity in semitopological monoids and semilattices”, Semigroup Forum, 107, № 3, 2023,
718