Undeclared work and legal instruments for combating it in Spain. Spanish Labour Law and Employment Relations Journal, [S. l.], v. 7, n. 1-2, p. 29–40, 2018. DOI: 10.20318/sllerj.2018.4434. Disponível em: https://e-revistas.uc3m.es/index.php/SLLERJ/article/view/4434. Acesso em: 5 dec. 2025.