1. World Health Organization; 2015. World report on ageing and health [Internet] [cited by 2019 Sep 25]. Available from https://apps.who.int/iris/handle/10665/186463
2. https://www.un.org/ru/global-issues/ageing
3. The population of the Russian Federation by gender and age as of January 1, 2021 (statistical bulletin). Federal State Statistics Service (ROSSTAT). Moscow, 2021. https://rosstat.gov.ru/storage/mediabank/Bul_chislen_nasel-pv_01-01-2021.pdf
4. Postoperative Delirium and Postoperative Cognitive Dysfunction
5. Perioperative management of geriatric patients