W. KOSIŃSKI, Z. NOWAK, and R. PĘCHERSKI, “Professor Piotr Perzyna - in memoriam”, Eng. Trans., vol. 61, no. 3, pp. 167–171, Sep. 2013, Accessed: Jan. 17, 2026. [Online]. Available: http://et.ippt.gov.pl/index.php/et/article/view/13