“Remarks on Zasada efektywności w prawie międzynarodowym [Principle of effectiveness in international law] by Janusz Symonides: On the Anniversary of the Conclusion of the Polish-German Treaties of 1950, 1970 and 1990” (2021) Polish Yearbook of International Law, 40, pp. 23–38. doi:10.24425/pyil.2021.138427.