EBANKS, Bruce. Sine subtraction laws on semigroups. Annales Mathematicae Silesianae, [S. l.], v. 37, n. 1, p. 49–66, 2023. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/15209. Acesso em: 2 jul. 2025.