DERECH, V. D. Characterization of the semilattice of idempotents of a finite-rank permutable inverse semigroup with zero. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 59, n. 10, p. 1353–1362, 2007. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3394. Acesso em: 5 dec. 2025.