1. Varnai, P. (2018). The silver economy in the European Union. Brussels, Belgium: European Commission; Directorate-General for Communications Networks, Content and Technology. Retrieved from http://publications.europa.eu/resource/cellar/2dca9276-3ec5-11e8-b5fe-01aa75ed71a1.0002.01/DOC_1. Accessed December 5, 2021.
2. Eatock, D. (2015, July 16). The silver economy: Opportunities from ageing. European Parliament. Research Service. Retrieved from https://epthinktank.eu/2015/07/16/the-silver-economy-opportunities-from-ageing/. Accessed December 5, 2021.
3. United Nations. (1982). Report of the world assembly on aging Vienna. Retrieved from https://www.un.org/esa/socdev/ageing/documents/Resources/VIPEE-English.pdf. Accessed December 5, 2021.
4. United Nations. (1991). United Nations principles on older persons. Retrieved from https://www.un.org/ru/documents/decl_conv/conventions/oldprinc.shtml. Accessed December 5, 2021.
5. United Nations. (2002). Madrid international plan of action on ageing. Retrieved from https://www.un.org/ru/documents/decl_conv/declarations/ageing_program.shtml. Accessed December 5, 2021.