“Social Dumping” and “Letterbox Companies” – Interdependent or Mutually Exclusive Concepts in European Union Law?. Polish Yearbook of International Law, [S. l.], v. 36, p. 209–229, 2016. DOI: 10.7420/pyil2016j. Disponível em: https://czasopisma.inp.pan.pl/index.php/pyil/article/view/2613. Acesso em: 3 oct. 2025.