Lenart, Łukasz, and Mateusz Pipień. “Non-Parametric Test for the Existence of the Common Deterministic Cycle The Case of the Selected European Countries”. Central European Journal of Economic Modelling and Econometrics 9, no. 3 (August 1, 2017): 201–241. Accessed February 28, 2026. https://wydawnictwo.pan.pl/index.php/cejeme/article/view/150.