Harasim, Janina. “Consumer Payment Habits and the Opportunity to Decrease the Cash in Circulation in Poland”. Krakow Review of Economics and Management Zeszyty Naukowe Uniwersytetu Ekonomicznego W Krakowie, no. 2(938), Nov. 2015, pp. 17-30, https://doi.org/10.15678/ZNUEK.2015.0938.0202.