Olender, Mieczysław. “A Report on the Scientific Conference: ‘The History of the Borderland. Centuries-Old Relations Between the Inhabitants of the Kurpie, Mazury and Warmia Regions’”. Echa Przeszłości, no. XVIII, Nov. 2018, https://czasopisma.uwm.edu.pl/index.php/ep/article/view/2131.