Kp. Proceedings ofthe 10th Polish Symposium of Physics in Economy and Social Sciences : Otwock-Świerk, Poland, July 3-5, 2019 / editors of the proceedings: Paweł Sobkowicz, Ryszard Kutner. - Warsaw, 2020.

OPI online

pl.wikipedia, 18.11.2020 https://pl.wikipedia.org/wiki/Pawe%C5%82_Sobkowicz#Linki_zewn%C4%99trzne