ŠLAPAL, Josef. Categories of universal algebras in which direct products are tensor products. Annales Mathematicae Silesianae, [S. l.], v. 9, p. 7–10, 1995. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14199. Acesso em: 8 may. 2025.