AHN, S. S. .; KIM, H. S. .; LEE, H. D. . On $Hom(-,-)$ as difference algebras. Tamkang Journal of Mathematics, [S. l.], v. 37, n. 1, p. 57–65, 2006. DOI: 10.5556/j.tkjm.37.2006.179. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/179. Acesso em: 3 may. 2024.