Karpio, Andrzej, and Dorota Żebrowska-Suchodolska. “POLISH OPEN-END PENSION FUNDS PERFORMANCE AND ITS PERSISTANCE”. Acta Scientiarum Polonorum. Oeconomia 15, no. 1 (March 30, 2016): 15-25. Accessed May 3, 2024. https://js.wne.sggw.pl/index.php/aspe/article/view/4208.