Szypniewski, Michał. “Self-Employment in the Light of Pursuit of Activities in Other Member States”. Acta Universitatis Lodziensis. Folia Iuridica 101 (December 29, 2022): 215–222. Accessed December 7, 2025. https://www.czasopisma.uni.lodz.pl/Iuridica/article/view/15839.