Borowski, Krzysztof. 2015. “An Analysis of Selected Seasonal Rates of Return on the Silver Market from 30.10.2003 to 31.12.2013”. Krakow Review of Economics and Management Zeszyty Naukowe Uniwersytetu Ekonomicznego W Krakowie, no. 1(937) (November): 5-26. https://doi.org/10.15678/ZNUEK.2015.0937.0101.