AMSilR. “Report of Meeting. The Fourth Debrecen-Katowice Winter Seminar on Functional Equations and Inequalities February 4-7, 2004 Matráháza, Hangary”. Annales Mathematicae Silesianae, Vol. 18, Sept. 2004, pp. 65-75, https://journals.us.edu.pl/index.php/AMSIL/article/view/14092.