Węgrzyn, Ryszard. 2015. “Changes in the Strength of Connections and the Volatility of Indices of the World Stock Exchanges”. Krakow Review of Economics and Management Zeszyty Naukowe Uniwersytetu Ekonomicznego W Krakowie, no. 2(938) (November): 111-28. https://doi.org/10.15678/ZNUEK.2015.0938.0209.