van Weeghel, Stef. “Reflections on Separate Enterprise Vs. Formulary Apportionment”. In Challenges of Contemporary Tax Law: Jubilee Book Dedicated to Professor Włodzimierz Nykiel. Volume II, edited by Ziemowit Kukulski and Małgorzata Sęk, 351–359. Poland: Lodz University Press, 2024. Accessed January 26, 2026. https://www.press.uni.lodz.pl/index.php/wul/catalog/book/1154/chapter/3175.