The requirement to obtain a Vander Elst visa for workers posted to Germany who are nationals of third countries as an example of a violation of the freedom to provide services. Dyskurs Prawniczy i Administracyjny [Internet]. 2024 Feb. 9 [cited 2025 Dec. 5];(1):37-52. Available from: https://www.dyskurs.inp.uz.zgora.pl/index.php/DPiA/article/view/316