GABOVICH, E. Endomorphisms of some ordered semi-groups. Lithuanian Mathematical Journal, [S. l.], v. 3, n. 2, p. 69–76, 1963. DOI: 10.15388/LMJ.1963.19449. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19449.. Acesso em: 19 jul. 2024.