OŚLIZŁO-DOSKOCZ, Natalia. Violation of the principle of legal certainty on the example of Art. 13 sec. 1a of the law on court fees. Studia Iuridica Toruniensia. Online. 10 October 2018. Vol. 21, pp. 259-270. [Accessed 5 July 2025]. DOI 10.12775/SIT.2017.037.