Kurkiewicz, Jolanta, and Ewa Soja. “Ageing and Informal Support for the Elderly in Selected European Countries”. Krakow Review of Economics and Management Zeszyty Naukowe Uniwersytetu Ekonomicznego W Krakowie, no. 11(947), May 2016, pp. 5-17, https://doi.org/10.15678/ZNUEK.2015.0947.1101.