Kp. Proceedings of combined conference 13th Econophysics Colloquium (EC) and 9th Symposium of Physics in Economy and Social Sciences (FENS) : University of Warsaw, 2017 July 5-7, Warsaw, Poland / editors of proceedings: Dariusz Grech and Ryszard Kutner. - Warsaw, 2018. Wstęp: (The (thirteenth) Econophysics Colloquium (EC2017) combined with [...] (ninth) Polish Symposium of Physics in Economy and Social Sciences (Polish acronym FENS2017) [...])