6.
Klich-Rączka A, Siuda J, Piotrowicz K, Boczarska-Jedynak M, Skalska A, Krzystanek E, et al. [Cognitive impairment in the elderly]. In: Mossakowska M, Więcek A, Błędowski P., editors. [Medical, psychological, sociological and economic aspects of population aging in Poland]. Poznań: Termedia Wydawnictwa Medyczne; 2012. p. 109-121 (in Polish).