Sojka, Elżbieta. “Process of Ageing of Śląskie Voivodship Population Until 2035”. Bulletin of Geography. Socio-economic Series, no. 16 (December 1, 2011): 121–138. Accessed March 29, 2024. https://apcz.umk.pl/BGSS/article/view/v10089-011-0018-5.